[Pw_forum] Phonon frequency

[henry odhiambo]

Hello colleagues,
 
I am calculating the phonon frequencies for stable ( or hexagonal) GST (Ge2Sb2Te5). I am getting some negative values (contrary to the notion of stability and literature). I used the unrelaxed structure to do the calculations. Could this be the reason?
 
Henry Otunga
Dept. of Physics
Maseno UNiversity
Kenya  
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