Splitting the Electron? No, Not Really
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Orbiton-Phonon Coupling in Ir5+(5D4) Double Perovskite Ba2yiro6
5+ 4 Orbiton-Phonon coupling in Ir (5d ) double perovskite Ba2YIrO6 Birender Singh1, G. A. Cansever2, T. Dey2, A. Maljuk2, S. Wurmehl2,3, B. Büchner2,3 and Pradeep Kumar1* 1School of Basic Sciences, Indian Institute of Technology Mandi, Mandi-175005, India 2Leibniz-Institute for Solid State and Materials Research, (IFW)-Dresden, D-01171 Dresden, Germany 3Institute of Solid State Physics, TU Dresden, 01069 Dresden, Germany ABSTRACT: 5+ 4 Ba2YIrO6, a Mott insulator, with four valence electrons in Ir d-shell (5d ) is supposed to be non-magnetic, with Jeff = 0, within the atomic physics picture. However, recent suggestions of non-zero magnetism have raised some fundamental questions about its origin. Focussing on the phonon dynamics, probed via Raman scattering, as a function of temperature and different incident photon energies, as an external perturbation. Our studies reveal strong renormalization of the phonon self-energy parameters and integrated intensity for first-order modes, especially redshift of the few first-order modes with decreasing temperature and anomalous softening of modes associated with IrO6 octahedra, as well as high energy Raman bands attributed to the strong anharmonic phonons and coupling with orbital excitations. The distinct renormalization of second-order Raman bands with respect to their first-order counterpart suggest that higher energy Raman bands have significant contribution from orbital excitations. Our observation indicates that strong anharmonic phonons coupled with electronic/orbital degrees of freedom provides a knob for tuning the conventional electronic levels for 5d-orbitals, and this may give rise to non-zero magnetism as postulated in recent theoretical calculations with rich magnetic phases. -
Multiple Spin-Orbit Excitons and the Electronic Structure of Α-Rucl3
PHYSICAL REVIEW RESEARCH 2, 042007(R) (2020) Rapid Communications Multiple spin-orbit excitons and the electronic structure of α-RuCl3 P. Warzanowski,1 N. Borgwardt,1 K. Hopfer ,1 J. Attig,2 T. C. Koethe ,1 P. Becker,3 V. Tsurkan ,4,5 A. Loidl,4 M. Hermanns ,6,7 P. H. M. van Loosdrecht,1 and M. Grüninger 1 1Institute of Physics II, University of Cologne, D-50937 Cologne, Germany 2Institute for Theoretical Physics, University of Cologne, D-50937 Cologne, Germany 3Section Crystallography, Institute of Geology and Mineralogy, University of Cologne, D-50674 Cologne, Germany 4Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, D-86135 Augsburg, Germany 5Institute of Applied Physics, MD-2028 Chisinau, Moldova 6Department of Physics, Stockholm University, AlbaNova University Center, SE-106 91 Stockholm, Sweden 7Nordita, KTH Royal Institute of Technology and Stockholm University, SE-106 91 Stockholm, Sweden (Received 20 November 2019; accepted 21 September 2020; published 13 October 2020) The honeycomb compound α-RuCl3 is widely discussed as a proximate Kitaev spin-liquid material. This = / 5 scenario builds on spin-orbit entangled j 1 2 moments arising for a t2g electron configuration with strong spin-orbit coupling λ and a large cubic crystal field. The actual low-energy electronic structure of α-RuCl3, however, is still puzzling. In particular, infrared absorption features at 0.30, 0.53, and 0.75 eV seem to be at odds with a j = 1/2 scenario. Also the energy of the spin-orbit exciton, the excitation from j = 1/2to3/2, and thus the value of λ, are controversial. -
The Pauli Exclusion Principle the Pauli Exclusion Principle Origin, Verifications, and Applications
THE PAULI EXCLUSION PRINCIPLE THE PAULI EXCLUSION PRINCIPLE ORIGIN, VERIFICATIONS, AND APPLICATIONS Ilya G. Kaplan Materials Research Institute, National Autonomous University of Mexico, Mexico This edition first published 2017 © 2017 John Wiley & Sons, Ltd. Registered Office John Wiley & Sons, Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United Kingdom For details of our global editorial offices, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at www.wiley.com. The right of the author to be identified as the author of this work has been asserted in accordance with the Copyright, Designs and Patents Act 1988. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The publisher is not associated with any product or vendor mentioned in this book. Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. -
Observing Spinons and Holons in 1D Antiferromagnets Using Resonant
Summary on “Observing spinons and holons in 1D antiferromagnets using resonant inelastic x-ray scattering.” Umesh Kumar1,2 1 Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN 37996, USA 2 Joint Institute for Advanced Materials, The University of Tennessee, Knoxville, TN 37996, USA (Dated Jan 30, 2018) We propose a method to observe spinon and anti-holon excitations at the oxygen K-edge of Sr2CuO3 using resonant inelastic x-ray scattering (RIXS). The evaluated RIXS spectra are rich, containing distinct two- and four-spinon excitations, dispersive antiholon excitations, and combinations thereof. Our results further highlight how RIXS complements inelastic neutron scattering experiments by accessing charge and spin components of fractionalized quasiparticles Introduction:- One-dimensional (1D) magnetic systems are an important playground to study the effects of quasiparticle fractionalization [1], defined below. Hamiltonians of 1D models can be solved with high accuracy using analytical and numerical techniques, which is a good starting point to study strongly correlated systems. The fractionalization in 1D is an exotic phenomenon, in which electronic quasiparticle excitation breaks into charge (“(anti)holon”), spin (“spinon”) and orbit (“orbiton”) degree of freedom, and are observed at different characteristic energy scales. Spin-charge and spin-orbit separation have been observed using angle-resolved photoemission spectroscopy (ARPES) [2] and resonant inelastic x-ray spectroscopy (RIXS) [1], respectively. RIXS is a spectroscopy technique that couples to spin, orbit and charge degree of freedom of the materials under study. Unlike spin-orbit, spin-charge separation has not been observed using RIXS to date. In our work, we propose a RIXS experiment that can observe spin-charge separation at the oxygen K-edge of doped Sr2CuO3, a prototype 1D material. -
The New Boson N
The New Boson N Luca Nascimbene1, 1Institute technology A.Maserati, street mussini nr.22,[email protected] Abstract The elementary particles that make up the universe can distinguish in particle-matter, of a fermionic type (quark, neutrino and neutrino, mass-equipped) and force-particles, bosonic type, carrying the fundamental forces in nature (photons and gluons, , And the W and Z bosons, endowed with mass). The Standard Model contemplates several other unstable particles that exist under certain conditions for a variable time, but still very short, before decaying into other particles. Among them there is at least one Higgs boson, which plays a very special role. The bosonic N, is an elementary discovery discovery thanks to various electronic devices and sensors. All this is a physical-electronic theoretical study. This particle seen on the oscilloscope has a different shape from the other, in particular it moves by looking at the oscilloscope and has a round shape. Keywords Boson;particles; 1. Introduction In particle physics, an elementary particle or fundamental particle is a particle whose substructure is unknown; thus, it is unknown whether it is composed of other particles. Known elementary particles include the fundamental fermions (quarks, leptons, antiquarks, and antileptons), which generally are "matter particles" and "antimatter particles", as well as the fundamental bosons (gauge bosons and the Higgs boson), which generally are "force particles" that mediate interactions among fermions. A particle containing two or more elementary particles is a composite particle. Everyday matter is composed of atoms, once presumed to be matter's elementary particles—atom meaning "unable to cut" in Greek— although the atom's existence remained controversial until about 1910, as some leading physicists regarded molecules as mathematical illusions, and matter as ultimately composed of energy. -
Nature Physics News and Views, January 2008
NEWS & VIEWS SupeRCONducTIVITY Beyond convention For high-temperature superconductors, results from more refined experiments on better-quality samples are issuing fresh challenges to theorists. It could be that a new state of matter is at play, with unconventional excitations. Didier Poilblanc antiferromagnetic insulator changes to as a function of an applied magnetic is in the Laboratoire de Physique Théorique, a superconductor — two very distinct field) in the magnetic-field-induced CNRS and Université Paul Sabatier, F-31062 states of matter. Their theory aims, in normal phase5, a fingerprint of small Toulouse, France. particular, to reconcile two seemingly closed Fermi surfaces named ‘pockets’. e-mail: [email protected] conflicting experimental observations. A valid theoretical description should Angular-resolved photoemission then account simultaneously for the lthough copper-oxide spectroscopy (ARPES) provides a unique destruction of the Fermi surface seen superconductors share with experimental set-up to map the locus in ARPES and for the SdH quantum A conventional superconductors of the zero-energy quasiparticles in oscillations. It should also explain the the remarkable property of offering no momentum space. Instead of showing a apparent violation of the Luttinger resistance to the flow of electricity, their large Fermi surface as most metals would, sum rule, the observed area of the SdH characteristic critical temperatures (Tc) above Tc low-carrier-density cuprates pockets being significantly smaller than below which this happens can be as show enigmatic ‘Fermi arcs’ — small the doping level (in appropriate units). high as 135 K. In fact, these materials disconnected segments in momentum A key feature of Kaul and colleagues’ belong to the emerging class of so-called space that continuously evolve into nodal theory1 is the emergence of a fractional strongly correlated systems — a class of points at Tc (ref. -
On the Orbiton a Close Reading of the Nature Letter
return to updates More on the Orbiton a close reading of the Nature letter by Miles Mathis In the May 3, 2012 volume of Nature (485, p. 82), Schlappa et al. present a claim of confirmation of the orbiton. I will analyze that claim here. The authors begin like this: When viewed as an elementary particle, the electron has spin and charge. When binding to the atomic nucleus, it also acquires an angular momentum quantum number corresponding to the quantized atomic orbital it occupies. As a reader, you should be concerned that they would start off this important paper with a falsehood. I remind you that according to current theory, the electron does not have real spin and real charge. As with angular momentum, it has spin and charge quantum numbers. But all these quantum numbers are physically unassigned. They are mathematical only. The top physicists and journals and books have been telling us for decades that the electron spin is not to be understood as an actual spin, because they can't make that work in their equations. The spin is either understood to be a virtual spin, or it is understood to be nothing more than a place-filler in the equations. We can say the same of charge, which has never been defined physically to this day. What does a charged particle have that an uncharged particle does not, beyond different math and a different sign? The current theory has no answer. Rather than charge and spin and orbit, we could call these quantum numbers red and blue and green, and nothing would change in the theory. -
Fractional Excitations in the Luttinger Liquid
Fractional Excitations in the Luttinger Liquid. K.-V. Pham, M. Gabay and P. Lederer Laboratoire de Physique des Solides, associ´eau CNRS Universit´eParis–Sud 91405 Orsay, France (September 18, 2018) We reconsider the spectrum of the Luttinger liquid (LL) usually understood in terms of phonons (density fluctuations), and within the context of bosonization we give an alternative representation in terms of fractional states. This allows to make contact with Bethe Ansatz which predicts similar fractional states. As an example we study the spinon operator in the absence of spin rotational invariance and derive it from first principles: we find that it is not a semion in general; a trial Jastrow wavefunction is also given for that spinon state. Our construction of the new spectroscopy based on fractional states leads to several new physical insights: in the low-energy limit, we find that the Sz = 0 continuum of gapless spin chains is due to pairs of fractional quasiparticle-quasihole states which are the 1D counterpart of the Laughlin FQHE quasiparticles. The holon operator for the Luttinger liquid with spin is also derived. In the presence of a magnetic field, spin-charge separation is not realized any longer in a LL: the holon and the spinon are then replaced by new fractional states which we are able to describe. PACS Numbers: 71.10 Pm , 71.27+a I. INTRODUCTION. the latter model is a fixed point of the renormalization group (RG)13. In 1D, bosonization allows to transform A. Motivations of this work. the Tomonaga-Luttinger model into a gaussian acoustic hamiltonian describing free phonons14; the considerable success and popularity of bosonization stems from the One of the most striking property of some strongly correlated systems is fractionalization, that is the exis- fact that all the computations are straightforward be- tence of elementary excitations carrying only part of the cause the effective hamiltonian is that of a free bosonic quantum numbers of the constituent particles of the sys- field. -
Two Models for New Cooper Pairs Gudrun Kalmbach H
Scholars International Journal of Chemistry and Material Sciences Abbreviated Key Title: Sch Int J Chem Mater Sci ISSN 2616-8669 (Print) |ISSN 2617-6556 (Online) Scholars Middle East Publishers, Dubai, United Arab Emirates Journal homepage: http://saudijournals.com Review Article Two Models for New Cooper Pairs Gudrun Kalmbach H. E* MINT PF 1533, D-86818 Bad Woerishofen, Germany DOI: 10.36348/sijcms.2020.v03i10.003 | Received: 24.11.2020 | Accepted: 23.12.2020 | Published: 29.12.2020 *Corresponding author: Gudrun Kalmbach H. E Abstract The author has recommended that for pairs of physical systems or qualities the method of energy exchange is studied, especially when the Cooper pairing can be applied. Keywords: Cooper pair, MINT-Wigris tool. Copyright © 2020 The Author(s): This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC BY-NC 4.0) which permits unrestricted use, distribution, and reproduction in any medium for non-commercial use provided the original author and source are credited. INRODUCTION Wigris project is new. The usual way to consider them There are many publications for combined as a pair of electrons is extended to the pairing of a spins in physics. The author refers in this article not to deuterons two nucleons and to the condensor plate them. The proposal for Cooper pairings in the MINT- pairing of two Hopf leptons in Figure-1 [1-4]. Fig-1: At left a proton and a neutron of deuteron are shown as two tetrahedrons having a common center in the middle; for the pairing of two condensor plates the four diagonals in the middle figure have a center B which is in the right figure split into four tips Bj of orthogonal vector pairs connecting the twisted condensor plates vertices 1,2,3,4 The new Cooper pairs are called fusion states For deuteron fusion a proton decays its u- for the deuteron since a twist arises where the lower quark which has another u-quark as partner in the tetrahedron is rotated by 180 degrees such that the twisted figure. -
Slave Particle Studies of the Electron Momentum Distribution in the Low
Slave Particle Studies of the Electron Momentum Distribution in the Low Dimensional t − J Model Shiping Feng∗,1 J. B. Wu,2 Z. B. Su,1,2 and L. Yu1,2 1International Centre for Theoretical Physics, P. O. Box 586, 34100 Trieste, Italy 2Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100080, China The electron momentum distribution function in the t − J model is studied in the framework of slave particle approach. Within the decoupling scheme used in the gauge field and related theories, we treat formally phase and amplitude fluctuations as well as constraints without further approximations. Our result indicates that the arXiv:cond-mat/9304011v1 8 Apr 1993 electron Fermi surface observed in the high-resolution angle-resolved photoemission and inverse photoemission experiments cannot be explained within this framework, and the sum rule for the physical electron is not obeyed. A correct scaling behavior of the electron momentum distribution function near k ∼ kF and k ∼ 3kF in one dimension can be reproduced by considering the nonlocal string fields [Z. Y. Weng et al., Phys. Rev. B45, 7850 (1992)], but the overall momentum distribution is still not correct, at least at the mean field level. PACS numbers: 71.45. -d, 75.10. Jm 1 I. INTRODUCTION The t−J model is one of the simplest models containing the essence of strong correlations and its implications for oxide superconductivity [1,2] still remain an outstanding problem. The t − J model was originally introduced as an effective Hamiltonian of the Hubbard model in the strong coupling regime, where the on-site Coulomb repulsion U is very large as compared with the electron hopping energy t, and therefore the electrons become strongly correlated to avoid the double occupancy. -
Spinon-Holon Binding in T-J Model
PHYSICAL REVIEW B 71, 172509 ͑2005͒ Spinon-holon binding in t-J model Tai-Kai Ng Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong ͑Received 21 December 2004; published 27 May 2005͒ Using a phenomenological model, we discuss the consequences of spinon-holon binding in the U͑1͒ slave- boson approach to t-J model in the weak-coupling limit. We find that spinon-holon binding produces a pseudogap normal state with a segmented Fermi surface and the superconducting state is formed by opening an “additional” d-wave gap on the segmented Fermi surface. The d-wave gap merges with the pseudogap smoothly as temperature T!0. The quasiparticles in the superconducting state are coupled to external elec- tromagnetic field with a coupling constant of order x␥/2 ͑x=hole concentration͒, where 0ഛ␥ഛ1. DOI: 10.1103/PhysRevB.71.172509 PACS number͑s͒: 74.20.Mn, 74.25.Jb ͑ ͒ ͑ ͒ ͑ ͒ ␥͑ជ͒ ͓ ͑ ͒ ͑ ͔͒ The U 1 slave-boson mean-field theory SBMFT of the where j=i+ ˆ =x,y , and k =2 cos kx +cos ky . t-J model has been used by many authors as a starting point ⌬͑kជ͒=͑3J/4͒⌬¯ (cos͑k ͒−cos͑k ͒) is a spinon pairing field for the theory of high-T superconductors.1–4 With suitable x y c ⌬¯ ͗ ͘ refinements, the theory can explain a lot of the qualitative where = fi"f j# − fi#f j" . The mean-field dispersion for the 2–5 ͑ជ͒ ͱ2 ͉⌬͑ជ͉͒2 1,5 features of the cuprates. -
One-Dimensional Cuprates Attract the Attention of Solid-State Physicists for Many Reasons
Current spinon-holon description of the one-dimensional charge-transfer insulator SrCuO2: Angle-resolved photoemission measurements A. Koitzsch1,2, S. V. Borisenko1, J. Geck1, V. B. Zabolotnyy1, M. Knupfer1, J. Fink1, P. Ribeiro1, B. Büchner1,2, R. Follath3 1 IFW Dresden, P.O.Box 270116, D-01171Dresden, Germany 2 Institute for Solid State Physics, TU Dresden, D-01062 Dresden, Germany 3 BESSY GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany Abstract: We have investigated the low-energy electronic structure of the strongly corre- lated one-dimensional copper oxide chain compound SrCuO2 by angle resolved photo- emission as a function of excitation energy. In addition to the prominent spinon-holon continuum we observe a peaklike and dispersive feature at the zone boundary. By fine- tuning the experimental parameters we are able to monitor the full holon branch and to directly measure the electronic hopping parameter with unprecedented accuracy. 1 One-dimensional cuprates attract the attention of solid-state physicists for many reasons. Among them almost perfect examples of one dimensional spin ½ Heisenberg chains can be found [1, 2]. It is well known that the standard models for the description of their low- energy electronic excitations spectacularly fail: a single electronic excitation decomposes into two independent excitations carrying either spin (spinons) or charge (holons) [3, 4]. While being conceptually highly important in its own right, the spin-charge separation promotes another striking peculiarity of these systems, namely the large non-linear opti- cal response, which renders these materials even technologically interesting [5, 6]. More specifically, external electrical fields tune the optical parameters enabling the construc- tion of optical switches [7].