This tutorial explains how to perform a spin-polarized calculation and how to perform the electronic structure analysis.
To calculate a system with spin polarization, one needs to set NSPIN=2 and nonzero initial magnetizatin (ZETA1). With this input file, densities of states projected onto the atomic orbitals (AO_LDOS or PDOS) are printed in the output file.
0 0 0 0 0 0 5.00 15.00 1 1 1 : GMAX, GMAXP, NTYP, NATM, NATM2 225 2 : num_space_group, type 6.70 6.700 6.700 90.00 90.00 90.00 : a,b,c,alpha,beta,gamma 16 16 16 1 1 1 : K_mesh 0 0 : NCORD, NINV, : IWEI, IMDTYP, ITYP 0.00 0.00 0.00 1 0 1 : CPS(1,1:3) IWEI IMDTYP ITYP 28 0.50 58.69 6 1 0.1 : IATOMN,ALFA,AMION,ILOC,IVAN ZETA1 0 0 0 0 0 : ICOND INIPOS INIVEL ININOS INIACC 0 1 : IPRE IPRI 30 30 0 84200.00 0 : NMD1 NMD2 LAST_ITER CPUMAX IFSTOP 6 1 : WAY_MIX MIX_WHAT 0 20 0.30 : ITER_START KBXMIX MIX_ALPHA 0.20 0.30 0.20 0.20 0.20 : DTIM1 DTIM2 DTIM3 DTIM4 DTIM 300.00 4 1 0.50D-09 : DTIO IMDALG IEXPL EDELTA -10.020 0.50D+03 0 : WIDTH FORCCR ISTRESS ggapbe 2 : XCTYPE KSPIN 2.00 : DESTM 102 : NBZTYP 4 4 4 : NKX NKY NKZ (DUMMY) 4 4 4 : NKX2 NKY2 NKZ2 (DUMMY) 24 : KEG 1 : NEXTST 0 : (DUMMY) 2 : IMSD 0 : EVALUATE_EKO_DIFF 1 : NPDOSAO 1 : IPDOST -15.00 5.00 0.20 501 : EPDOS(1) EPDOS(2) EPDOS(3) NPDOSE 2.40 0.20 : RPDOS(1) RPDOS(2) 0.20 14 : DR NR 0 0.00 : DUMMY DUMMY
After the SCF calculation, perform a non-SCF band structure calculation by setting ICOND=22 and high-symmetry k-points in the &KPOINTS_BAND...&END block
0 0 0 0 0 0 5.00 15.00 1 1 1 : GMAX, GMAXP, NTYP, NATM, NATM2 225 2 : num_space_group, type 6.70 6.700 6.700 90.00 90.00 90.00 : a,b,c,alpha,beta,gamma 16 16 16 1 1 1 : K_mesh 0 0 : NCORD, NINV, : IWEI, IMDTYP, ITYP 0.00 0.00 0.00 1 0 1 : CPS(1,1:3) IWEI IMDTYP ITYP 28 0.50 58.69 6 1 0.1 : IATOMN,ALFA,AMION,ILOC,IVAN 22 0 0 0 0 : ICOND INIPOS INIVEL ININOS INIACC 0 1 : IPRE IPRI 30 30 0 84200.00 0 : NMD1 NMD2 LAST_ITER CPUMAX IFSTOP 6 1 : WAY_MIX MIX_WHAT 0 20 0.30 : ITER_START KBXMIX MIX_ALPHA 0.20 0.30 0.20 0.20 0.20 : DTIM1 DTIM2 DTIM3 DTIM4 DTIM 300.00 4 1 0.50D-09 : DTIO IMDALG IEXPL EDELTA -10.020 0.50D+03 0 : WIDTH FORCCR ISTRESS ggapbe 2 : XCTYPE KSPIN 2.00 : DESTM 102 : NBZTYP 4 4 4 : NKX NKY NKZ (DUMMY) 4 4 4 : NKX2 NKY2 NKZ2 (DUMMY) 24 : KEG 1 : NEXTST 0 : (DUMMY) 2 : IMSD 0 : EVALUATE_EKO_DIFF 0 : NPDOSAO 0 0.00 : DUMMY DUMMY &KPOINTS_BAND NKSEG 4 KMESH 40 20 20 20 KPOINTS 0.000 0.000 0.000 0.000 0.500 0.500 0.250 0.500 0.750 0.500 0.500 0.500 0.000 0.000 0.000 &END
To plot the band strcture of a spin polarized system, perfrom the following
> energy2band -s
and input the number of bands, the number of bands used to plot the band, the number of k-points, and the Fermi level. DO NOT remember to add the option "-s", which is necessary for the spin-polarized system. Then one obtain "band_up.data" and "band_dw.data", which can be used to plot the band structure using gnuplot, xmgrace, or alike. Here is an example of the gnuplot script
set terminal postscript eps 'Helvetica' 22 set output 'band.eps' emin=-10.0 emax=10.0 xmin=0.0 xmax=2.88194910 G=0.0 X=0.93778885 W=1.40668328 L=2.06980013 G2=2.88194910 offset=0.75 set xrange [xmin:xmax] set yrange [emin:emax] set key top left unset xtics unset xlabel set ylabel 'E-E_F (eV)' set xzeroaxis set arrow from X,emin to X,emax nohead set arrow from W,emin to W,emax nohead set arrow from L,emin to L,emax nohead set label '{/Symbol G}' at G,emin-offset center set label 'X' at X,emin-offset center set label 'W' at W,emin-offset center set label 'L' at L,emin-offset center set label '{/Symbol G}' at G2,emin-offset center plot 'band_up.data' using 1:2 with lines title 'Spin-up' lt 1 lw 3, 'band_dw.data' using 1:2 with lines title 'Spin-down' lt 2 lw 3