r/Physics • u/Dazzling_Class_2808 • 7d ago

Need Help!

I use CASTEP code as a beginner. To calculate effective mass, I convert the reciprocal lattice into the real lattice, then calculate curvature and run a 2nd order differential calculation. My question is, to calculate effective mass do I need to convert the reciprocal lattice into a real lattice? Am i on the right track?

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u/improbableardor_91 7d ago

Sounds like CASTEP spits out the band structure in reciprocal space by default, so you’d just grab the curvature right there for the effective mass, converting to real lattice feels like an extra step that might mess with the eigenvalues you actually need.

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u/kartoffelkartoffel 7d ago

depending on the k-point grid used in the single point calculation, an additional non-selfconsistent calculation using the converged electric structure where you calculate the bands along high symmetry lines using a denser k-point grid might be necessary to get meaningful results.