Lecture 2.2 Plasma and Sheath.Pdf

Total Page:16

File Type:pdf, Size:1020Kb

Lecture 2.2 Plasma and Sheath.Pdf Introduction to Nuclear Engineering, Fall 2018 Plasma and Sheath Fall, 2018 Kyoung-Jae Chung Department of Nuclear Engineering Seoul National University Motions in uniform electric field Equation of motion of a charged particle in fields = ( , ) + × ( , ) , = ( ) Motion in constant electric field For a constant electric field = with = 0, ( ) = + + 2 Electrons are easily accelerated by electric field due to their smaller mass than ions. Electrons (Ions) move against (along) the electric field direction. The charged particles get kinetic energies. 2/38 Introduction to Nuclear Engineering, Fall 2018 Motions in uniform magnetic field Motion in constant magnetic field = × For a constant magnetic field = 0 with = 0, = 0 = −0 = 0 Cyclotron (gyration) frequency = = 2 2 0 2 − 3/38 Introduction to Nuclear Engineering, Fall 2018 Motions in uniform magnetic field Particle velocity = cos + = sin + ⊥ 0 = 0 −⊥ 0 Particle position = sin + + sin = cos + + cos = + 0 0 − 0 0 0 − 0 0 0 Guiding center , , + Larmor0 0(gyration)0 0 radius = = ⊥ ⊥ 0 4/38 Introduction to Nuclear Engineering, Fall 2018 Gyro-frequency and radius The direction of gyration is always such that the magnetic field generated by the charged particle is opposite to the externally imposed field. diamagnetic For electrons = 2.80 × 10 Hz in gauss 6 0 0 3.37 = cm ( in volts) 0 For singly charged ions = 1.52 × 10 / Hz in gauss 3 0 0 144 = cm ( in volts, in amu) Energy gain?0 5/38 Introduction to Nuclear Engineering, Fall 2018 Motions in uniform E and B fields Equation of motion = + × Parallel motion: = 0 and = 0 , = = + 0 Straightforward acceleration along B 6/38 Introduction to Nuclear Engineering, Fall 2018 × drift Transverse motion: = 0 and = 0 , = + = 0 0 −0 Differentiating, = 2 2 2 = − + × 2 = 2 0 2 − 0 Particle velocity = cos + = ⊥ sin +0 0 ⊥ 0 − − 0 7/38 Introduction to Nuclear Engineering, Fall 2018 DC magnetron A magnetron which is widely used in the sputtering system uses the × drift motion for plasma confinement. What is the direction of × drift motion? 8/38 Introduction to Nuclear Engineering, Fall 2018 Motions in gravitational field Generally, the guiding center drift caused by general force 1 × = If is the force of gravity , × = What is the difference between and ? 9/38 Introduction to Nuclear Engineering, Fall 2018 ⊥ : Grad-B drift The gradient in | | causes the Larmor radius to be larger at the bottom of the orbit than at the top, and this should lead to a drift, in opposite directions for ions and electrons, perpendicular to both and . Guiding center motion 1 × = ± 2 ⊥ 10/38 Introduction to Nuclear Engineering, Fall 2018 Curved B: Curvature drift The average centrifugal force = = 2 ∥ 2 � ∥ 2 Curvature drift 1 × × = = 2 1 ∥ 2 ∝ Total drift in a curved vacuum field (curvature + grad-B) × 1 + = + = 2 2 2 ∥ ⊥ 2 2 2 − 11/38 Introduction to Nuclear Engineering, Fall 2018 ∥ : Magnetic mirror Adiabatic invariant: Magnetic moment 1 2 = = 2 ⊥ As the particle moves into regions of stronger or weaker , its Larmor radius changes, but remains invariant. Magnetic mirror 1 1 2 2 2 = 2 ⊥0 ⊥ 0 = + 2 2 2 2 ⊥ ⊥0 ∥0 ≡ 0 = = = sin 2 2 0 ⊥0 ⊥0 2 2 2 ⊥ 0 12/38 Introduction to Nuclear Engineering, Fall 2018 Motions in a dipole magnetic field Trajectories of particles confined in a dipole field Particles experience gyro-, bounce- and drift- motions 13/38 Introduction to Nuclear Engineering, Fall 2018 Boltzmann’s equation & macroscopic quantities Particle density Particle flux Particle energy density 14/38 Introduction to Nuclear Engineering, Fall 2018 Particle conservation + = � − The net number of particles per second generated within either flows across the surface or increases the number of particles withinΩ . Γ Ω For common low-pressure discharges in steady-state: = , 0 ≈ Hence, = � The continuity equation is clearly not sufficient to give the evolution of the density , since it involves another quantity, the mean particle velocity . 15/38 Introduction to Nuclear Engineering, Fall 2018 Momentum conservation Convective derivative Pressure tensor isotropic for weakly ionized plasmas The time rate of momentum transfer per unit volume due to collisions with other species + = � − − 16/38 Introduction to Nuclear Engineering, Fall 2018 Equation of state (EOS) An equation of state is a thermodynamic equation describing the state of matter under a given set of physical conditions. = , , = ( , ) Isothermal EOS for slow time variations, where temperatures are allowed to equilibrate. In this case, the fluid can exchange energy with its surroundings. = , = Theenergy conservation equation needs to be solved to determine p and T. Adiabatic EOS for fast time variations, such as in waves, when the fluid does not exchange energy with its surroundings = , = = (specific heat ratio) The energy conservation equation is not required. 2 Specific heat ratio vs degree of freedom ( ) = 1 + 17/38 Introduction to Nuclear Engineering, Fall 2018 Equilibrium: Maxwell-Boltzmann distribution For a single species in thermal equilibrium with itself (e.g., electrons), in the absence of time variation, spatial gradients, and accelerations, the Boltzmann equation reduces to = 0 � Then, we obtain the Maxwell-Boltzmann velocity distribution 2 = 3 2 2 − 2 / 2 = 1 2 − The mean speed / = 1 2 8 ̅ 18/38 Introduction to Nuclear Engineering, Fall 2018 Particle and energy flux The directed particle flux: the number of particles per square meter per second crossing the = 0 surface in the positive direction / = 1 2 푡 1 = 4 Γ ̅ The average energy flux: the amount of energy per square meter per second in the +z direction 1 = = 2 2 2Γ The average kinetic energy per particle crossing = 0 in the positive direction = 2 19/38 Introduction to Nuclear Engineering, Fall 2018 Diffusion and mobility The fluid equation of motion including collisions = + = � − − In steady-state, for isothermal plasmas 1 1 = = − − = = ± − Drift − Diffusion In terms of particle flux = Einstein relation = = ± ∶ − = Mobility = Diffusion coefficient ∶ ∶ 20/38 Introduction to Nuclear Engineering, Fall 2018 Ambipolar diffusion The flux of electrons and ions out of any region must be equal such that charge does not build up. Since the electrons are lighter, and would tend to flow out faster in an unmagnetized plasma, an electric field must spring up to maintain the local flux balance. = + = AmbipolarΓ electric − field for = Γ − − = Γ Γ + − The common particle flux + = = + Γ − − The ambipolar diffusion coefficient for weakly ionized plasmas + T = + 1 + ~ T + Te e ≈ ≈ i 21/38 Introduction to Nuclear Engineering, Fall 2018 Steady-state plane-parallel solutions Diffusion equation volume source and sink = 2 − − For a plane-parallel geometry with no volume source or sink = 0 = + 2 B.C. = 0 = − 2 = Γ = /2 =Γ00 2 Γ0 − is determined For a uniform specified source of diffusing particles 0 B.C. symmetric at = 0 = 1 = 2 2 2 0 = ± /2 = 0 2 − 2 0 − The most common case is for a plasma8 consisting of positive ions and an equal number of electrons which are the source of ionization + = 0 where, = and is the ionization frequency 2 22/38 Introduction to Nuclear Engineering, Fall 2018 Boltzmann’s relation The density of electrons in thermal equilibrium can be obtained from the electron force balance in the absence of the inertial, magnetic, and frictional forces + = � − − − Setting = and assuming = −Φ = ln= 0 Integrating,Φ − we have Φ − = exp = exp T Boltzmann’s relation for electrons 0 Φ 0 Φ e ( ) For positive ions in thermal equilibrium at temperature T ( ) = exp i T 0 Φ However, positive ions are almost never in thermal equilibrium in low pressure− i discharges because the ion drift velocity is large, leading to inertial or frictional forces comparable to the electric field or pressure gradient forces. 23/38 Introduction to Nuclear Engineering, Fall 2018 Debye shielding (screening) Plasma Coulomb potential Poisson’s equation = = 1 / = 4 2 2 0 Φ 0 Φ Φ Φ − − ≈ Φ 2 Screened Coulomb0 potential Debye length0 0 / / = exp T 4 = 1 2 = 1 2 0 0 e Φ − 2 0 0 0 24/38 Introduction to Nuclear Engineering, Fall 2018 Debye length The electron Debye length is the characteristic length scale in a plasma. The Debye length is the distance scale over which significant charge densities can spontaneously exist. For example, low-voltage (undriven) sheaths are typically a few Debye lengths wide. 10 -3 Typical values for a processing plasma (ne = 10 cm , Te = 4 eV) T T eV 4 cm = = 743 = 743 0.14 mm 1⁄2 cm 10 0 e e −3 10 0 0 ≈ Quasi-neutrality? + It is on space scales larger than a Debye length that the - plasma will tend to remain neutral. - - + + The Debye length serves as a characteristic scale length + - - to shield the Coulomb potentials of individual charged λ + particles when they collide. D 25/38 Introduction to Nuclear Engineering, Fall 2018 Quasi-neutrality The potential variation across a plasma of length can be estimated from Poisson’s equation ≫ ~ ~ 2 Φ 2 Φ 0 − We generally expect that T = 2 Φ ≲ e Then, we obtain 0 1 2 − 2 Plasma approximation ≲ ≪ = The plasma approximation
Recommended publications
  • Plasma Oscillation in Semiconductor Superlattice Structure
    Memoirs of the Faculty of Engineering,Okayama University,Vol.23, No, I, November 1988 Plasma Oscillation in Semiconductor Superlattice Structure Hiroo Totsuji* and Makoto Takei* (Received September 30, 1988) Abstract The statistical properties of two-dimensional systems of charges in semiconductor superlattices are analyzed and the dispersion relation of the plasma oscillation is ealculated. The possibility to excite these oscillations by applying the electric field parallel to the structure is discussed. ]. Introduction The layered structure of semiconductors with thickness of the order of lO-6 cm or less is called semiconductor superlattice. The superlattice was first proposed by Esaki and Tsu [11 as a structure which has a Brillouin zone of reduced size and therefore allows to apply the negative mass part of the band structure to electronic devices through conduction of carriers perpendicular to the structure. The superlattice has been realized by subsequent developments of technologies such as molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD) in fabricating controlled fine structures. At the same time, many interesting and useful physical phenomena related to the parallel conduction have also been revealed in addition to the parallel conduction. From the view point of application to devices, the enhancement of the carrier mobility due to separation of channels from Ionized impurities may be one of the most important progresses. Some high speed devices are based on this technique. The superlattlce structure
    [Show full text]
  • Carbon Fiber Skeleton/Silver Nanowires Composites with Tunable Negative
    EPJ Appl. Metamat. 8, 1 (2021) © Y. An et al., published by EDP Sciences, 2021 https://doi.org/10.1051/epjam/2020019 Available online at: epjam.edp-open.org Metamaterial Research Updates from China RESEARCH ARTICLE Carbon fiber skeleton/silver nanowires composites with tunable negative permittivity behavior Yan An1, Jinyuan Qin1, Kai Sun1,*, Jiahong Tian1, Zhongyang Wang2,*, Yaman Zhao1, Xiaofeng Li1, and Runhua Fan1 1 College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai 201306, PR China 2 State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR China Received: 13 November 2020 / Accepted: 25 December 2020 Abstract. With the development of periodic metamaterials, more attention has been paid to negative permittivity behavior due to great potential applications. In this paper, silver nanowires (AgNWs) were introduced to the porous carbon fibers (CFS) by an impregnation process to prepare CFS/AgNWs composites with different content of AgNWs and the dielectric property was investigated. With the formation of conductive network, the Drude-like negative permittivity was observed in CFS/AgNWs composites. With the increase of AgNWs, the connectivity of conductive network became enhanced, the conductivity gradually increases, and the absolute value of the negative dielectric constant also increases to 8.9 Â 104, which was ascribed to the enhancement of electron density of the composite material. Further investigation revealed that the inductive characteristic was responsible for the negative permittivity. Keywords: Negative permittivity / metacomposites / plasma oscillation / inductive characteristic 1 Introduction capacitors [10,11]. The electromagnetic metamaterials have a great value in the fields of wireless communication In the past decades, electromagnetic metamaterials with [12], electromagnetic absorption [13] and shielding [14], etc.
    [Show full text]
  • Free Electron Lasers and High-Energy Electron Cooling*
    FREE ELECTRON LASERS AND HIGH-ENERGY ELECTRON COOLING* Vladimir N. Litvinenko, BNL, Upton, Long Island, NY, USA# Yaroslav S. Derbenev, TJNAF, Newport News, VA, USA) Abstract The main figure of merit of any collider is its average Cooling intense high-energy hadron beams remains a luminosity, i.e., its average productivity for an appropriate major challenge in modern accelerator physics. branch of physics. Cooling hadron beams at top energy Synchrotron radiation of such beams is too feeble to may further this productivity. provide significant cooling: even in the Large Hadron For a round beam, typical for hadron colliders, the Collider (LHC) with 7 TeV protons, the longitudinal luminosity is given by a simple expression: ' * damping time is about thirteen hours. Decrements of N1N2 & s traditional electron cooling decrease rapidly as the high L = fc * % h) * , (1) 4"# $ ( # + power of beam energy, and an effective electron cooling of protons or antiprotons at energies above 100 GeV where N1, N2 are the number of particles per bunch, fc is seems unlikely. Traditional stochastic cooling still cannot their collision frequency, !* is the transverse !-function catch up with the challenge of cooling high-intensity at the collision point, " is the transverse emittance of the bunched proton beams - to be effective, its bandwidth b!ea m, #s is the bunch length, and h ! 1 is a coefficient must be increased by about two orders-of-magnitude. accounting for the so-called hourglass effect [1]: Two techniques offering the potential to cool high- " 1/ x 2 h(x) = e erfc(1/ x). energy hadron beams are optical stochastic cooling (OSC) x and coherent electron cooling (CEC) – the latter is the The hourglass effect is caused by variations in the beam’s 2 focus of this paper.
    [Show full text]
  • The Effect Pressure on Wavelengths of Plasma Oscillations in Argon And
    AN ABSTRACT OF TI-lE TRESIS OF - ¡Idgar for Gold.an the ri,, s. in (Name) (Degree) (Najor) Date Thesis presented ia. i9i__ Title flTO PSDEo LPLASMA OSeILLATIos..iN - Abstract Approved (-(Najor Professor) Experiments on argon and. nitrogen are described. which show that the wave length of electromaetjc radiation emitted from a gas plasma in a magnetic field is a function of the pressure of the gas. This result is Consistent with the theory of plasma oscillation developed by Tonics and Langniir if the assumption is made that plasma electron density is a function of gas pressure. A lower limit of wave length plasma of oscillation is indicated by the experiments in qualitative agreement with the Debye length equation, No difference in the wave length-tressn, relationship between the two gases was observed. The experimental tube, which consisted of a gas filled cylindrical anode with an axial tungsten filament) was motmted. in a magnetic field parallel to the axis of the anode. Gas pressures between i and 50 microns and. magnetic fields between 500 and 1,000 gauss were used. The anode voltage was aplied. in short pulses in order to mini- mize heating of the cathode by ion bombardment and to make possible the use of alternating voltage amplifiers in the receiver. The receiver of electromagnetic radiation consisted. of a crystal- detector dipole, constructed from a 1N26 crystal cartridge, followed by a video amp1ifier The amplifier had a maximum gain of 1.6 X iO7, and. a bandwidth of 2 megacycles Wave lengths were measured by means of an interferometer.
    [Show full text]
  • Introduction to Metamaterials
    FEATURE ARTICLE INTRODUCTION TO METAMATERIALS BY MAREK S. WARTAK, KOSMAS L. TSAKMAKIDIS AND ORTWIN HESS etamaterials (MMs) are artificial structures LEFT-HANDED MATERIALS designed to have properties not available in To describe the basic properties of metamaterials, let us nature [1]. They resemble natural crystals as recall Maxwell’s equations M they are build from periodically arranged (e.g., square) unit cells, each with a side length of a. The ∂H ∂E ∇×E =−μμand ∇×H = εε (1) unit cells are not made of physical atoms or molecules but, 00rr∂tt∂ instead, contain small metallic resonators which interact μ ε with an external electromagnetic wave that has a wave- where the r and r are relative permeability and permit- λ ⎡ ∂ ∂ ∂ ⎤ length . The manner in which the incident light wave tivity, respectively, and L =⎢ ,,⎥ . From the above ⎣⎢∂xy∂ ∂z ⎦⎥ interacts with these metallic “meta-atoms” of a metamate- equations, one obtains the wave equation rial determines the medium’s electromagnetic proper- ties – which may, hence, be made to enter highly unusual ∂2E ∇=−2E εμεμ (2) regimes, such as one where the electric permittivity and 00rr∂t 2 the magnetic permeability become simultaneously (in the ε μ same frequency region) negative. If losses are ignored and r and r are considered as real numbers, then one can observe that the wave equation is ε The response of a metamaterial to an incident electromag- unchanged when we simultaneously change signs of r and μ netic wave can be classified by ascribing to it an effective r . (averaged over the volume of a unit cell) permittivity ε ε ε μ μ μ To understand why such materials are also called left- eff = 0 r and effective permeability eff = 0 r .
    [Show full text]
  • Plasma Waves
    Plasma Waves S.M.Lea January 2007 1 General considerations To consider the different possible normal modes of a plasma, we will usually begin by assuming that there is an equilibrium in which the plasma parameters such as density and magnetic field are uniform and constant in time. We will then look at small perturbations away from this equilibrium, and investigate the time and space dependence of those perturbations. The usual notation is to label the equilibrium quantities with a subscript 0, e.g. n0, and the pertrubed quantities with a subscript 1, eg n1. Then the assumption of small perturbations is n /n 1. When the perturbations are small, we can generally ignore j 1 0j ¿ squares and higher powers of these quantities, thus obtaining a set of linear equations for the unknowns. These linear equations may be Fourier transformed in both space and time, thus reducing the differential equations to a set of algebraic equations. Equivalently, we may assume that each perturbed quantity has the mathematical form n = n exp i~k ~x iωt (1) 1 ¢ ¡ where the real part is implicitly assumed. Th³is form descri´bes a wave. The amplitude n is in ~ general complex, allowing for a non•zero phase constant φ0. The vector k, called the wave vector, gives both the direction of propagation of the wave and the wavelength: k = 2π/λ; ω is the angular frequency. There is a relation between ω and ~k that is determined by the physical properties of the system. The function ω ~k is called the dispersion relation for the wave.
    [Show full text]
  • What Is Plasma? Its Characteristics Plasma Oscillations Plasmon And
    Topics covered here are: What is Plasma? Its Characteristics Plasma Oscillations Plasmon and plasmon frequency Sources used here are: http://farside.ph.utexas.edu/teaching/plasma/Plasmahtml/node1.html https://www.britannica.com/science/plasma-state-of-matter/Plasma-oscillations- and-parameters What is Plasma The electromagnetic force is generally observed to create structure: e.g., stable atoms and molecules, crystalline solids. Structured systems have binding energies larger than the ambient thermal energy. Placed in a sufficiently hot environment, they decompose: e.g., crystals melt, molecules disassociate. At temperatures near or exceeding atomic ionization energies, atoms similarly decompose into negatively charged electrons and positively charged ions. These charged particles are by no means free: in fact, they are strongly affected by each others' electromagnetic fields. Nevertheless, because the charges are no longer bound, their assemblage becomes capable of collective motions of great vigor and complexity. Such an assemblage is termed a plasma. Of course, bound systems can display extreme complexity of structure: e.g., a protein molecule. Complexity in a plasma is somewhat different, being expressed temporally as much as spatially. It is predominately characterized by the excitation of an enormous variety of collective dynamical modes. Its occurrence and characteristics Since thermal decomposition breaks interatomic bonds before ionizing, most terrestrial plasmas begin as gases. In fact, a plasma is sometimes defined as a gas that is sufficiently ionized to exhibit plasma-like behavior. Note that plasma-like behavior ensues after a remarkably small fraction of the gas has undergone ionization. Thus, fractionally ionized gases exhibit most of the exotic phenomena characteristic of fully ionized gases.
    [Show full text]
  • Plasma Oscillations in Heavy-Fermion Materials A
    Plasma oscillations in heavy-fermion materials A. J. Millis, M. Lavagna, P.A. Lee To cite this version: A. J. Millis, M. Lavagna, P.A. Lee. Plasma oscillations in heavy-fermion materials. Physical Review B: Condensed Matter (1978-1997), American Physical Society, 1987, 36 (1), pp.864-867. 10.1103/Phys- RevB.36.864. hal-01896336 HAL Id: hal-01896336 https://hal.archives-ouvertes.fr/hal-01896336 Submitted on 16 Oct 2018 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. PHYSICAL REVIEW B VOLUME 36, NUMBER 1 1 JULY 1987 Plasma oscillations in heavy-fermion materials A. J. Millis AT& T Bell Laboratories, 600 Mountain Avenue, Murray Hill, New Jersey 07974 M. Lavagna Laboratoire Louis Neel, Centre National de la Recherche Scientifique, Boite Postale No. 166x, 38042 Grenoble Cedex France P. A. Lee Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (Received 2 February 1987) We calculate the dielectric function of the lattice Anderson model via an auxiliary-boson large-N method suitably generalized to include the eA'ects of the long-range part of the Coulomb interaction. We show that the model exhibits a low-lying plasma oscillation at a frequency m* on the order of the Kondo temperature of the model, in addition to the usual high-frequency plasma oscillation.
    [Show full text]
  • Tunable Acoustic Double Negativity Metamaterial SUBJECT AREAS: Z
    Tunable acoustic double negativity metamaterial SUBJECT AREAS: Z. Liang1, M. Willatzen2,J.Li1 & J. Christensen3 CONDENSED-MATTER PHYSICS FLUIDS 1Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, 2Mads Clausen Institute, University of Southern Denmark, Alsion 2, DK-6400 Sønderborg, Denmark, 3IQFR - CSIC Serrano 119, 28006 MATERIALS SCIENCE Madrid, Spain. PHYSICS Man-made composite materials called ‘‘metamaterials’’ allow for the creation of unusual wave propagation Received behavior. Acoustic and elastic metamaterials in particular, can pave the way for the full control of sound in 16 August 2012 realizing cloaks of invisibility, perfect lenses and much more. In this work we design acousto-elastic surface modes that are similar to surface plasmons in metals and on highly conducting surfaces perforated by holes. Accepted We combine a structure hosting these modes together with a gap material supporting negative modulus and 11 October 2012 collectively producing negative dispersion. By analytical techniques and full-wave simulations we attribute the observed behavior to the mass density and bulk modulus being simultaneously negative. Published 14 November 2012 lassical waves such as sound and light have recently been put to the test in the challenges for cloaking objects1–8 and realizing negative refraction9–18. Those concepts are just a few of recent fascinating phe- Correspondence and nomena which are consequences of artificial electromagnetic (EM) or acoustic metamaterial designs. C 19 20 Perfect imaging or enhanced transmission of waves in subwavelength apertures are other disciplines within requests for materials the scope of metamaterials which have received considerable attention both from a theoretical and experimental should be addressed to point of view21–24.
    [Show full text]
  • Tunable Reflectionless Absorption of Electromagnetic Waves in a Plasma- Metamaterial Composite Structure
    Plasma Sources Science and Technology ACCEPTED MANUSCRIPT Tunable reflectionless absorption of electromagnetic waves in a plasma- metamaterial composite structure To cite this article before publication: Nolan Uchizono et al 2020 Plasma Sources Sci. Technol. in press https://doi.org/10.1088/1361- 6595/aba489 Manuscript version: Accepted Manuscript Accepted Manuscript is “the version of the article accepted for publication including all changes made as a result of the peer review process, and which may also include the addition to the article by IOP Publishing of a header, an article ID, a cover sheet and/or an ‘Accepted Manuscript’ watermark, but excluding any other editing, typesetting or other changes made by IOP Publishing and/or its licensors” This Accepted Manuscript is © 2020 IOP Publishing Ltd. During the embargo period (the 12 month period from the publication of the Version of Record of this article), the Accepted Manuscript is fully protected by copyright and cannot be reused or reposted elsewhere. As the Version of Record of this article is going to be / has been published on a subscription basis, this Accepted Manuscript is available for reuse under a CC BY-NC-ND 3.0 licence after the 12 month embargo period. After the embargo period, everyone is permitted to use copy and redistribute this article for non-commercial purposes only, provided that they adhere to all the terms of the licence https://creativecommons.org/licences/by-nc-nd/3.0 Although reasonable endeavours have been taken to obtain all necessary permissions from third parties to include their copyrighted content within this article, their full citation and copyright line may not be present in this Accepted Manuscript version.
    [Show full text]
  • Collective Modes of the Massless Dirac Plasma
    Collective modes of the massless Dirac plasma S. Das Sarma and E. H. Hwang Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742-4111 and Kavli Institute for Theoretical Physics, Santa Barbara, California 93106 (Dated: April 26, 2009) We develop a theory for the long-wavelength plasma oscillation of a collection of charged massless Dirac particles in a solid, as occurring for example in doped graphene layers, interacting via the long-range Coulomb interaction. We find that the long-wavelength plasmon frequency in such a doped massless Dirac plasma is explicitly non-classical in all dimensions with the plasma frequency being proportional to 1/√!. We also show that the long wavelength plasma frequency of the D- dimensional superlattice made from such a plasma does not agree with the corresponding D +1 dimensional bulk plasmon frequency. We compare and contrast such Dirac plasmons with the well- studied regular palsmons in metals and doped semiconductors which manifest the usual classical long wavelength plasma oscillation. PACS numbers: 52.27.Ny; 81.05.Uw; 71.45.Gm A collection of charged particles (i.e. a plasma), elec- ‘!’ appearing manifestly in the long wavelength plasma trons or holes or ions, is characterized by a collective frequency in D = 1, 2, 3 dimension (and in between). mode associated with the self-sustaining in-phase den- By contrast the long wavelength plasma frequency of or- sity oscillations of all the particles due to the restoring dinary electron liquids is classical, and quantum effects force arising from the long-range 1/r Coulomb poten- show up only as nonlocal corrections in higher order wave tial.
    [Show full text]
  • Arxiv:Cond-Mat/0408683V1 [Cond-Mat.Mtrl-Sci] 31 Aug 2004 Onaisi Ocueteapaec Fanw”Lowered” New a of ¯ at Appearence Loss the Cause to Is Boundaries Mass
    Surface plasmons in metallic structures J. M. Pitarke,1,2, V. M. Silkin,2 E. V. Chulkov,2,3, and P. M. Echenique2,3 1Materia Kondentsatuaren Fisika Saila, Zientzi Fakultatea, Euskal Herriko Unibertsitatea, 644 Posta kutxatila, E-48080 Bilbo, Basque Country, Spain 2Donostia International Physics Center (DIPC) and Centro Mixto CSIC-UPV/EHU, Manuel de Lardizabal Pasealekua, E-20018 Donostia, Basque Country, Spain 3Materialen Fisika Saila, Kimika Fakultatea, Euskal Herriko Unibertsitatea, 1072 Posta kutxatila, E-20080 Donostia, Basque Country, Spain (Dated: September 5, 2018) Since the concept of a surface collective excitation was first introduced by Ritchie, surface plas- mons have played a significant role in a variety of areas of fundamental and applied research, from surface dynamics to surface-plasmon microscopy, surface-plasmon resonance technology, and a wide range of photonic applications. Here we review the basic concepts underlying the existence of surface plasmons in metallic structures, and introduce a new low-energy surface collective excitation that has been recently predicted to exist. PACS numbers: 71.45.Gm, 73.20.At, 78.47.+p, 78.68.+m I. INTRODUCTION the energy loss of charged particles moving outside a metal surface was shown to be due to the excitation 13,14 The long-range nature of the Coulomb interaction be- of surface plasmons, and the centroid of the elec- tween valence electrons in metals is known to yield collec- tron density induced by external potentials acting on a metal surface was demonstrated to be dictated by the tive behaviour, manifesting itself in the form of plasma 15 oscillations. Pines and Bohm1 were the first to suggest wave-vector dependence of surface plasmons.
    [Show full text]