[Pw_forum] Minor bug in matdyn.x

[Derek Stewart]

Hi everyone,

I wanted to report a very small bug in matdyn that I came across earlier 
this week.  It looks like matdyn will only add in the LO-TO splitting to 
the Gamma point if you specify the Gamma point as q=0,0,0.  If you use 
an equivalent form of the Gamma point, say q=1,1,1, the LO-TO splitting 
is not included.  I ran into this issue while doing some phonon 
dispersion calculations for cubic boron nitride.  For the Gamma-X high 
symmetry line, I used a non-traditional q-path going from [1,1,1] to 
[1,1,0] and noticed the LO-TO splitting was missing at the Gamma point 
there, but was included for the Gamma point q=0,0,0 later on in the 
phonon dispersion.

Best regards,

Derek



-- 
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Derek Stewart, Ph. D.
Senior Research Associate
http://sites.google.com/site/dft4nano/
250 Duffield Hall
Cornell Nanoscale Facility (CNF)
Ithaca, NY 14853
stewart (at) cnf.cornell.edu
(607) 255-2856