WIEN2k An Augmented Plane Wave Plus Local Orbitals Program for Calculating Crystal Properties User’s Guide, WIEN2k 21.1 (Release 04/30/2021) Peter Blaha Karlheinz Schwarz Georg K. H. Madsen Dieter Kvasnicka Joachim Luitz Robert Laskowski Fabien Tran Laurence D. Marks Vienna University of Technology Institute of Materials Chemistry Getreidemarkt 9/165-TC A-1060 Vienna, Austria Peter Blaha, Karlheinz Schwarz, Georg K. H. Madsen, Dieter Kvasnicka, Joachim Luitz, Robert Laskowski, Fabien Tran, Laurence D. Marks: WIEN2k An Augmented Plane Wave + Local Orbitals Program for Calculating Crystal Properties revised edition WIEN2k 21.1 (Release 04/30/2021) Prof. Dr. Karlheinz Schwarz Vienna University of Technology Institute of Materials Chemistry Getreidemarkt 9/165-TC A-1060 Vienna, Austria ISBN 3-9501031-1-2 ISBN 3-9501031-1-2 Contents I Introduction to the WIEN2k package1 1 Introduction 3 2 Basic concepts 7 2.1 Density Functional Theory..................................7 2.2 The APW Methods......................................8 2.2.1 The LAPW Method..................................8 2.2.2 The APW+lo Method................................. 10 2.2.3 General considerations................................ 10 3 Quick Start 13 3.1 Naming conventions..................................... 13 3.2 Starting the server....................................... 14 3.3 Connecting to the w2web server.............................. 15 3.4 Creating a new session.................................... 15 3.5 Creating a new case...................................... 16 3.6 Creating the struct file.................................... 16 3.7 Initialization.......................................... 18 3.8 The SCF calculation...................................... 20 3.9 The case.scf file........................................ 21 3.10 Saving a calculation...................................... 21 3.11 Calculating properties.................................... 21 3.11.1 Electron density plots................................ 21 3.11.2 Density of States (DOS)............................... 24 3.11.3 X-ray spectra..................................... 26 3.11.4 Bandstructure..................................... 26 3.11.5 Bandstructure with band character plotting / full lines............. 27 3.11.6 Volume Optimization................................ 28 3.12 Setting up a new case..................................... 29 3.12.1 Manual setup..................................... 29 3.12.2 Setting up a new case using w2web ........................ 29 II Detailed description of the files and programs of the WIEN2k package 31 4 Files and Program Flow 33 4.1 Flow of input and output files................................ 33 4.2 Input/Output files...................................... 37 4.3 The case.struct.file....................................... 38 4.4 The case.scf file........................................ 43 4.5 Flow of programs....................................... 44 4.5.1 Core, semi-core and valence states......................... 46 4.5.2 Spin-polarized calculation.............................. 46 4.5.3 Fixed-spin-moment (FSM) calculations...................... 47 4.5.4 Staggered field inside atomic spheres to vary the magnetic moment...... 47 4.5.5 Antiferromagnetic (AFM) calculations....................... 47 4.5.6 Spin-orbit interaction................................. 48 4.5.7 Orbital potentials................................... 49 4.5.8 Onsite-exact-exchange and hybrid functionals for correlated electrons.... 49 4.5.9 Unscreened and screened hybrid functionals (“hf”-module).......... 52 4.5.10 Slater, SmBJ and KLI potentials (“hf”-module).................. 57 4.5.11 Modified Becke-Johnson potential (mBJ) for band gaps............. 58 4.5.12 Local modified Becke-Johnson potential (lmBJ) for interfaces and systems with vacuum..................................... 59 4.5.13 GLLB-SC method................................... 60 4.5.14 DFT–1/2 method................................... 60 4.5.15 DFT-D3 and DFT-D4 for dispersion energy.................... 62 4.5.16 Nonlocal van der Waals functionals........................ 62 5 Shell scripts 65 5.1 Job control........................................... 65 5.1.1 Main execution script (x lapw)........................... 65 5.1.2 Create the master input file case.struct (makestruct lapw)........... 67 5.1.3 Job control for initialization (init lapw)...................... 67 5.1.4 Job control for iteration (run lapw or runsp lapw)................ 68 5.1.5 Job control for iteration with the Slater/SmBJ/KLI potentials (run vnonloc lapw).................................. 71 5.1.6 Job control for calculating the exchange discontinuity of the GLLB-SC method (run deltagllb lapw)............................ 72 5.2 Utility scripts......................................... 72 5.2.1 Save a calculation (save lapw)........................... 72 5.2.2 Restoring a calculation (restore lapw)....................... 73 5.2.3 Remove unnecessary files (clean lapw)...................... 73 5.2.4 Migrate a case to/from a remote computer (migrate lapw)........... 73 5.2.5 Set R-MT values in your case.struct file (setrmt lapw).............. 74 5.2.6 Generate case.inst (instgen lapw).......................... 74 5.2.7 Check for running WIEN jobs (check lapw).................... 74 5.2.8 Cancel (kill) running WIEN jobs (cancel lapw).................. 75 5.2.9 grepline lapw..................................... 75 5.2.10 scfmonitor lapw................................... 75 5.2.11 analyse lapw..................................... 76 5.2.12 Extract critical points from a Bader analysis (extractaim lapw)......... 76 5.2.13 Check parallel execution (testpara lapw)..................... 76 5.2.14 Check parallel execution of lapw1 (testpara1 lapw)............... 76 5.2.15 Check parallel execution of lapw2 (testpara2 lapw)............... 76 5.2.16 Create case.int file (for DOS) (configure int lapw)................ 76 5.2.17 init orb lapw..................................... 77 5.2.18 init so lapw...................................... 77 5.2.19 init hf lapw...................................... 78 5.2.20 init mbj lapw..................................... 78 5.2.21 vec2old lapw..................................... 78 5.2.22 joinvec lapw...................................... 79 5.2.23 Reduce atomic spheres and interpolate density (reduce rmt lapw)...... 79 5.2.24 clmextrapol lapw................................... 79 5.2.25 create add atom clmsum lapw........................... 79 5.3 Structure optimization.................................... 80 5.3.1 Lattice parameters (Volume, c/a, lattice parameters)............... 80 5.3.2 Minimization of internal parameters....................... 83 5.4 Phonon calculations...................................... 86 5.4.1 init phonon lapw................................... 87 5.4.2 analyse phonon lapw................................ 87 5.5 Parallel Execution....................................... 87 5.5.1 k-Point Parallelization................................ 88 5.5.2 MPI parallelization.................................. 88 5.5.3 How to use WIEN2k as a parallel program.................... 89 5.5.4 The .machines file................................. 89 5.5.5 How the list of k-points is split........................... 91 5.5.6 Flow chart of the parallel scripts.......................... 92 5.5.7 On the fine grained parallelization......................... 92 5.6 NMR calculations: Chemical shift and Knight shift.................... 94 5.6.1 Chemical shift..................................... 94 5.6.2 Knight shifts...................................... 99 5.7 Wannier functions (wien2wannier)............................. 100 5.7.1 Usage.......................................... 101 5.7.2 Help and FAQ..................................... 102 5.8 Spontaneous Polarization, Piezoelectricity and Born Charges (BerryPI)........ 102 5.8.1 Options........................................ 103 5.8.2 Spontaneous Polarization.............................. 103 5.8.3 Born effective charges................................ 104 5.8.4 Piezoelectric constants................................ 105 5.9 Getting on-line help...................................... 105 5.10 Interface scripts........................................ 106 5.10.1 eplot lapw....................................... 106 5.10.2 gibbs lapw....................................... 106 5.10.3 parabolfit lapw.................................... 107 5.10.4 dosplot lapw..................................... 107 5.10.5 dosplot2 lapw..................................... 108 5.10.6 Cgrace lapw, Cgrace conf lapw and Cgrace dos lapw............. 108 5.10.7 Curve lapw...................................... 108 5.10.8 specplot lapw..................................... 109 5.10.9 rhoplot lapw..................................... 109 5.10.10 prepare xsf lapw................................... 109 5.10.11 opticplot lapw.................................... 110 5.10.12 addjoint-updn lapw................................. 110 5.10.13 create elf lapw.................................... 111 6 Initialization 113 6.1 NN............................................... 113 6.1.1 Execution....................................... 114 6.2 SGROUP............................................ 114 6.2.1 Execution....................................... 114 6.3 SYMMETRY.......................................... 114 6.3.1 Execution....................................... 114 6.4 LSTART............................................. 115