Example for Fermi Surface plot added to example 8

git-svn-id: http://qeforge.qe-forge.org/svn/q-e/trunk/espresso@2147 c92efa57-630b-4861-b058-cf58834340f0

examples/example08/README

@@ -1,6 +1,6 @@
 
-This example shows how to use pw.x and dos.x to calculate the 
-Density of States (DOS) of Ni .
+This example shows how to calculate the Density of States (DOS) and
+how to plot the Fermi Surface of Ni .
 
 The calculation proceeds as follows (for the meaning of the cited input
 variables see the appropriate INPUT_* file)
@@ -25,3 +25,53 @@ variables see the appropriate INPUT_* file)
    'ni.pdos_tot', s and d component in files 'ni.pdos_atm#1(Ni)_wfc#1(s)'
    and 'ni.pdos_atm#1(Ni)_wfc#2(d)' respectively).  (input=ni.pdos.in,
    output=ni.pdos.in)
+
+5) Fermi Surface plot, courtesy of
+      Eyvaz Isaev
+      Theoretical Physics Department
+      Moscow State Institute of Steel and Alloys
+      (eyvaz_isaev@yahoo.com, e.isaev@misis.ru)
+   First, one generates a  grid of k-points (all of them, not only those
+   in the Irreducible Brilloin Zone) using auxiliary code kvecs_FS.x
+   Then, the non-scf calculation is performed
+   Then, auxiliary code bands_FS.x collects the data and produces a
+   file ni.fs.bxsf that can be read by XCrySDen (www.xcrysden.org) as:
+      xcrysden --bxsf ni.fs.bxsf 
+   Additional info for customization of the script:
+#
+# A user has to edit so-called "user part" in order to define some required 
+# parameters.
+# 
+# Sysname   - a nickname for your system
+# Calc_Type - The Fermi Surface calculations (FS) or band-structure
+#             calculations (Band) which will be included later. 
+#             Presently band-structure calculations could be carried out 
+#             by means of plotband.x from PP (postprocessing) directory 
+#             or a little package distributed by E.Isaev (posted to pw_forum). 
+# nabc      - a number for dividing of each edge of a parallelepiped.
+#             Be careful, the total number of generated k-points is
+#             (na+1)*(nb+1)*(nc+1), i.e. including \Gamma-point.
+# n_start   - starting band's number for the Fermi Surface calculations.
+#             It is obvious, we have to deal with the bands crossing the
+#             Fermi level.
+# n_last    - last band's number for FS calculations
+#
+# That's all!!! Present values in the script (may be edited):
+Sysname='ni'
+Calc_Type='FS'
+nabc=' 16 16 16 '
+n_start=2
+n_last=5
+#
+#
+# Nota Bene : You can take more bands and then choose from a XCrySDen menu
+#             only those bands which cross the Fermi level   
+# Nota Bene : If you have mistaken choosing bands to be considered for the
+#             FS construction, you do not need to restart all calculations.
+#             Just edit "bands_FS" file and restart "bands_FS.x" manually.
+#             It will read Bands.out and result Bands.bxsf which you can
+#             rename as you like.
+#  
+# Spin-polarized calculations are not allowed, but will be done soon.
+
+   

examples/example08/run_example

@@ -16,7 +16,7 @@ $ECHO "This example shows how to use pw.x to calculate the DOS of Ni."
 . ../environment_variables
 
 # required executables and pseudopotentials
-BIN_LIST="pw.x dos.x projwfc.x"
+BIN_LIST="pw.x dos.x projwfc.x kvecs_FS.x bands_FS.x"
 PSEUDO_LIST="NiUS.RRKJ3.UPF"
 
 $ECHO
@@ -66,10 +66,14 @@ $ECHO " done"
 PW_COMMAND="$PARA_PREFIX $BIN_DIR/pw.x $PARA_POSTFIX"
 DOS_COMMAND="$PARA_PREFIX $BIN_DIR/dos.x $PARA_POSTFIX"
 PROJWFC_COMMAND="$PARA_PREFIX $BIN_DIR/projwfc.x $PARA_POSTFIX"
+KVECS_COMMAND="$BIN_DIR/kvecs_FS.x "
+BANDS_COMMAND="$BIN_DIR/bands_FS.x "
 $ECHO
 $ECHO "  running pw.x as:      $PW_COMMAND"
 $ECHO "  running dos.x as:     $DOS_COMMAND"
 $ECHO "  running projwfc.x as: $PROJWFC_COMMAND"
+$ECHO "  running kvecs_FS.x as:  $KVECS_COMMAND"
+$ECHO "  running bands_FS.x as:  $BANDS_COMMAND"
 $ECHO
  
 # clean TMP_DIR
@@ -219,5 +223,110 @@ $ECHO "  running PDOS calculation for Ni...\c"
 $PROJWFC_COMMAND < ni.pdos.in > ni.pdos.out
 $ECHO " done"
 
+$ECHO "  Fermi Surface plot ...\c"
+
+# self-consistent calculation - spin-unpolarised this tie
+cat > ni.scf.in << EOF
+ &control
+    calculation='scf'
+    restart_mode='from_scratch',
+    prefix='ni',
+    pseudo_dir = '$PSEUDO_DIR/',
+    outdir='$TMP_DIR/'
+ /
+ &system
+    ibrav=2, celldm(1) =6.48, nat=1, ntyp=1,
+    ecutwfc = 24.0, ecutrho = 288.0,
+    occupations='smearing', smearing='methfessel-paxton', degauss=0.02
+ /
+ &electrons
+    conv_thr = 1.0e-8
+    mixing_beta = 0.7 
+ /
+ATOMIC_SPECIES
+ Ni 58.69 NiUS.RRKJ3.UPF
+ATOMIC_POSITIONS
+ Ni 0.0 0.0 0.0
+K_POINTS {automatic}
+ 8 8 8 0 0 0 
+EOF
+$ECHO "  running the scf calculation (no spin) ... \c"
+$PW_COMMAND < ni.scf.in > ni.scf0.out
+$ECHO " done"
+
+#
+# prepare input file ni.fs.in
+#
+Sysname='ni'
+Calc_Type='FS'
+nabc=' 12 12 12 '
+n_start=3
+n_last=6
+#
+E_Fermi=`grep Fermi ni.scf0.out | cut -c 26-36` 
+a1=`grep 'b(1)' ni.scf.out | cut -c 24-54`
+a2=`grep 'b(2)' ni.scf.out | cut -c 24-54`
+a3=`grep 'b(3)' ni.scf.out | cut -c 24-54`
+
+cat > kvecs_FS.in <<EOF
+$a1
+$a2
+$a3
+$nabc
+$Sysname
+EOF
+
+$KVECS_COMMAND < kvecs_FS.in > kvecs_FS,out
+
+cat > ni.fs.in << EOF
+ &control
+    calculation='nscf'
+    prefix='ni',
+    pseudo_dir = '$PSEUDO_DIR/',
+    outdir='$TMP_DIR/'
+ /
+ &system
+    ibrav=2, celldm(1) =6.48, nat=1, ntyp=1,
+    ecutwfc = 24.0, ecutrho = 288.0, nbnd=8
+ /
+ &electrons
+    conv_thr = 1.0e-8
+    mixing_beta = 0.7 
+ /
+ATOMIC_SPECIES
+ Ni 58.69 NiUS.RRKJ3.UPF
+ATOMIC_POSITIONS
+ Ni 0.0 0.0 0.0
+K_POINTS
+EOF
+
+cat  kvecs_$Sysname >> ni.fs.in
+
+# input file ni.fs.in ready
+$ECHO "  running the Fermi Surface calculation ... \c"
+$PW_COMMAND   < ni.fs.in > ni.fs.out 
+$ECHO " done"
+
+# prepare input data (input_FS, Bands.out) for bands_FS
+
+mv ni.fs.out Bands.out
+
+cat > input_FS <<EOF
+$n_start  $n_last
+$E_Fermi
+$Sysname
+$Calc_Type
+$nabc
+$a1
+$a2
+$a3
+EOF
+
+$BANDS_COMMAND > bands_fs.out
+mv Bands.bxsf  ni.fs.bxsf 
+
+$ECHO "  Fermi surface plot: use 'xcrysden --bxsf ni.fs.bxsf' to plot ...\c"
+$ECHO " done"
+
 $ECHO
 $ECHO "$EXAMPLE_DIR: done"