Hello Everyone, The common interband matrix element <m| dH/dkx \pm i dH\dky |n> seems to be calculable using DFT software. However, I am trying to calculate the tangential matrix element <m| dH/dt | n> \equiv <m| dH/dkx dkx/dt + dH/dky dky/dt |n> for some parameter t that parameterizes a closed loop in k-space: (kx(t),ky(t)) = (kx0+cos(t), ky0+sin(t)), where the loop center is (kx0,ky0). With my basic understanding of QE, I thought of a way to do this using a monolayer MoS2 example: I first sample k-points along a closed loop. This gives me wavefunctions in the .dat format. I was hoping to somehow extract wavefunction data to smoothen the gauge using the maximally localized Wannier function method, and manually calculate the matrix element I want using a central difference method with MATLAB or Python. However, I cannot seem to read the data from the .dat files. I saw several solutions in the archives that suggest using different existing routines that involve the evec variable. However, I am not familiar with Fortran90 and so have trouble figuring out how exactly to use such routines and custom code to get eigenvector data in a readable format. Does anyone have any advice or resources? I am using QE v6.6 Alternatively, are there other more-direct ways to go about calculating the quantity I want? Thank you very much for your time!
Tharindu W. Fernando PhD Student, University of Washington
_______________________________________________ Quantum ESPRESSO is supported by MaX (www.max-centre.eu) users mailing list [email protected] https://lists.quantum-espresso.org/mailman/listinfo/users
