LSPECTRALGW: Difference between revisions
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and should be selected for molecules and other systems with flat bands. | and should be selected for molecules and other systems with flat bands. | ||
One the other hand, {{TAG|LSPECTRALGW}} = .TRUE. seems to converge slightly slower, | One the other hand, {{TAG|LSPECTRALGW}} = .TRUE. seems to converge slightly slower, | ||
as the complex shift {{TAG|CSHIFT}} is decreased. | as the complex shift {{TAG|CSHIFT}} is decreased. Set this flag, if the QP energies | ||
show erratic behavior, for instance, if QP energies or Z-factors are not in the expected | |||
range of values. | |||
Revision as of 18:15, 13 March 2017
LSPECTRALGW = .FALSE. | .TRUE.
Default: LSPECTRALGW | = .FALSE. | {{{3}}} |
Description: LSPECTRALGW specifies to use the spectral method for calculating the self-energy.
If LSPECTRALGW = .TRUE. is set, the imaginary part of the self-energy is calculated from the imaginary part of screened potential by shifting the poles of by , where are the poles of the Green's function . Generally, LSPECTRALGW affects the compute time very little. QP energies also hardly change when LSPECTRALGW is modified. However, LSPECTRALGW = .TRUE. is usually is slightly more robust, and should be selected for molecules and other systems with flat bands. One the other hand, LSPECTRALGW = .TRUE. seems to converge slightly slower, as the complex shift CSHIFT is decreased. Set this flag, if the QP energies show erratic behavior, for instance, if QP energies or Z-factors are not in the expected range of values.