Messages

1

General Questions and Answers / WKB approximation

« on: January 14, 2020, 07:53 »

I am using QATK ver 2016.4 perpetual licence.

We have used Brenner (ASAP) potential parameter set for calculating the classical potential of a phonon (for SiNR and GeNR). Tersoff SiGe potential set is used with frozen phonon method. To calculate the phonon properties, i.e. forces and dynamical matrix 180 small displacements measuring 0.01 Ǻ are applied. The heat current is calculated considering the contribution of both electron and phonon. The transport calculations are carried out with the Landauer theory and the non-equilibrium Green’s function (NEGF) framework in Atomistix Tool Kit (ATK).

Is WKB approximation valid under such a scenario?

2

General Questions and Answers / Calculation of Fermi Velocity

« on: February 28, 2018, 03:46 »

I am currently using perpetual license of Quantumwise ATK version 2016.4.

I am simulating a graphene supercell and examining electronic properties. we have chosen slater koster calculator.

This is in reference to the paper in Computational Materials Science Vol - 141 (2018), Pg 353-359.

Want to calculate the Fermi velocity of graphene  supercell. Also want to calculate quantum capacitance.

Request the procedure.

3

General Questions and Answers / conjugate gradient optimisation

« on: April 13, 2016, 07:58 »

how to implement conjugate gradient optimisation in quantumwise?