Slide 43
Slide 43 text
Jarvist Moore Frost (ICL, UK) NanoGe Computational Perovskites 8th September 2020
Extend variational method to explicit sum over multiple
phonons
β(T,ω) = ħω/(kB⋅T)
F(v,w,T,ω
e
,α) = A(v,w,β(T,ω
e
)) +
B(v,w,β(T,ω
e
),α) +
C(v,w,β(T,ω
e
))
F(v,w,T,ω
e
,{ω
i
},{α
i
}) = A + ∑
i
B(v,w,β(T,ω
i
),α
i
) +
Explicit modes: solve variational problem with inner
loop over individual phonon modes (and thus phonon
frequency + electron-phonon coupling)
Still need an effective frequency for model Action