LSELFENERGY

LSELFENERGY = [logical]
Default: LSELFENERGY = .FALSE. 

Description: Controls whether the frequency-dependent self-energy is calculated or not.

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If LSELFENERGY=.FALSE., QP shifts are evaluated. This is the default behavior.

If LSELFENERGY=.TRUE., the frequency dependent self-energy $\langle \psi _{n{\mathbf {k} }}|\Sigma (\omega )|\psi _{n{\mathbf {k} }}\rangle$ is evaluated and printed to vasprun.xml. An example output looks like the following:

<varray name="selfenergy" >                                                                                                                                                                                                                                               
 <v>    -150.00000000     -25.40060536       0.24429448 </v>                                                                                                                                                                                                              
 <v>    -149.70000000     -25.40600800       0.24673910 </v>                                                                                                                                                                                                              
 <v>    -149.40000000     -25.41141065       0.24918372 </v>                                                                                                                                                                                                              
 <v>    -149.10000000     -25.41681330       0.25162834 </v>                                                                                                                                                                                                              
 <v>    -148.80000000     -25.42221682       0.25406890 </v>                                                                                                                                                                                                              
 <v>    -148.50000000     -25.42762671       0.25647992 </v>                                                                                                                                                                                                              
 <v>    -148.20000000     -25.43303731       0.25888834 </v>        

If quartic-scaling GW algorithms are selected, e.g. ALGO=EVGW0, the first column corresponds to points on the real-frequency axis. The second and third column are the real and imaginary parts of the self-energy at a given k-point and band index. In this case the evaluation of QP shifts is also bypassed and a small set of self-energy points are printed to OUTCAR instead, similar to the following output

calculating selfenergy CALC_SELFENERGY_LINEAR between w=-150.00 150.00                                                                                                                                                                                                     
                                                                                                                                                                                                                                                                           
k-point   1 :       0.0000    0.0000    0.0000                                                                                                                                                                                                                             
 band No.  band energies     occupation                                                                                                                                                                                                                                    
                                                  
     1     -11.7125      2.00000  selfenergy along real axis                                                                                                                                                                                                               
 -150.0000000   -25.4006054     0.2442945                                                                                                                                                                                                                                  
 -147.0000000   -25.4546849     0.2685030                                                                                                                                                                                                                                  
 -144.0000000   -25.5088867     0.2923888     
...

For low-scaling GW algorithms, the QP-energies are evaluated and printed to OUTCAR. In contrast, the vasprun.xml file now contains the self-energy on the imaginary frequency axis for the points selected by the Minimax routines.

<varray name="selfenergy along imaginary axis" >                                                                                                                                                                                                                          
  <v>       0.1570801806644298    -23.7971327349915711     -0.0179645094529067</v>                                                                                                                                                                                         
  <v>       0.4718033117773284    -23.7968260788831572     -0.0537856829291801</v>                                                                                                                                                                                         
  <v>       0.8108804505648752    -23.7966749072893577     -0.0932103588740998</v>                                                                                                                                                                                         
  <v>       1.3058951128526406    -23.7949927690568188     -0.1482973553314607</v>         
...

Here the number of evaluated frequency points depends on NOMEGA.

Related tags and articles

• for a practical guide to GW calculations
• ALGO for response functions and RPA calculations
• LFINITE_TEMPERATURE finite temperature formalism
• NOMEGA number of real or imaginary frequency points

Examples that use this tag

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