QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: ams_nanolab on December 20, 2012, 13:56

Title: About the directions in the eff mass analyzer
Post by: ams_nanolab on December 20, 2012, 13:56

I am looking to evaluate effective masses in a hexagonal system (graphene) at the K point in the K--> G and the K--> M directions. How to input that into the analyzer.

Also, is it okay to input fractional values like [1,1/sqrt(3),0] etc. into the direction box? or only [100], [010] etc. directions are allowed?

Title: Re: About the directions in the eff mass analyzer
Post by: Anders Blom on December 21, 2012, 10:43

The direction is normalized, so you can enter [0.5,0.5,0.5] or [0.1,0.1,0.1] or [111] - it all gives the same result. Note that the coordinates and direction are to be given in lattice coordinates, not Cartesian.

K->G = [-1,-1,0]
K->M = [-1,0,0]

(I mostly tested cubic systems while developing the analyzer, so let me know if you see anything out of the ordinary using these directions.)

Note that the linear dispersion of graphene at the K-point means the effective mass is hard to compute accurately.