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1

General Questions and Answers / Calculating Projected DOS Efficiently

« on: November 8, 2023, 11:39 »

I've been working with the DensityOfStates class with the default tetrahedral sampling method using the projection_list option in the .evaluate() function to calculate local density of states by specifying the appropriate atoms using ProjectionList(atoms=[...]). However, it seems that for every local density of states the progress bar indicating tetrahedral sampling is being conducted is displayed, indicating that the K-point sampling and eigenenergies are reevaluated. Even worse, when I call the .energies() or .fermiLevel() functions on a single DensityOfStates instance after calling .evaluate(), the tetrahedral resampling progress appears again. My calculations are currently limited by the DOS step, with average runtimes on my machine being on the scale of 5 hours for a single DOS calculation. I therefore was wondering if there is a way to take advantage of previously conducted calculations for DOS to avoid redundancy in LDOS calculations, thereby reducing computation time. My ultimate goal is to calculate LDOS (value, energy, and fermi level) for every atom of a structure with around one hundred atoms using a semiempirical approach.

2

General Questions and Answers / Simulations of HfO2-SiO2 Interactions

« on: October 4, 2023, 22:40 »

Dear ATK,

We're looking to do transport characterization for a large number of gate stacks between 150-250 atoms comprised of amorphous HfO2 and SiO2. We were hoping to use the semiempirical calculator since it's by far the fastest approach and we only need very rough DOS and band structure far from Ec, but it seems that no parameter sets are included for Hf-Si pairwise interaction. Is there a built-in approach to generate SK tight-binding parameters, perhaps from DFT simulations? Alternatively, is there a recommended approach for fast simulation of systems similar to ours with runtimes on the order of semiempirical approaches (perhaps a relatively simple pseudopotential with LCAO/DFT)?

Thank you,
Krishna