Dear all,
I have been using Phonon package ( version 6.1) to compute electron-phonon
coupling matrix elements. Following example 3 in Phonon package, I computed the
elements of Al(bcc) and the elements are written in
_ph0/al.phsave/elph.*.*.xml. According to phonon user’s guide and developer’s
manual, the elements in these files are coupling matrix in the basis of normal
mode, ie g_{q nu} and it has been scaled to phonon frequencies and masses.
However, if I manually change masses in Phonon input file, the elements do not
change. So, are you sure the elements are in normal mode basis and are scaled
to masses? Also, what is the unit for the elements written in those files? I
assume it is Rydberg?
Another question is about the elements at k=gamma and q=gamma. Because the
el-ph coupling matrix elements are computed with < psi_mk+q | dvscf | psi_nk >.
At k=gamma and q=gamma, I believe these quantities should be real numbers,
right? However, I get complex numbers for Al at k=gamma, q=gamma. Here are
first several elements:
<K_POINT.1>
<COORDINATES_XK type="real" size="3" columns="3">
0.000000000000000E+000 0.000000000000000E+000 0.000000000000000E+000
</COORDINATES_XK>
<PARTIAL_ELPH type="complex" size="100">
1.173453794238444E-007, 5.551115123125783E-017
-2.279566019787527E-002, 3.586239646544477E-001
-4.862786020311256E-001, 2.450200129592524E-001
3.623894552425257E+000,-5.173393946467373E-001
-6.097101185043030E-009, 1.009496251869191E-008
2.988349845356453E-010, 9.034043582656359E-010
2.767334139619493E-010, 1.470082250376592E-010
Do I make any mistake in computing or interpreting the results?
Here’s my input file for phonon calculation:
&inputph
tr2_ph=1.0d-10,
prefix='al',
fildvscf='aldv',
amass(1)=26.98,
fildyn='./_ph0/al.dyn',
outdir='./',
electron_phonon='yambo',
el_ph_sigma=0.005,
el_ph_nsigma=10,
asr = .true.
zue = .false.
epsil = .false.
trans=.true.,
ldisp=.true.
nq1=5, nq2=5, nq3=5
/
Thank you very much!
Han.
University of Chicago_______________________________________________
users mailing list
[email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
