Introduction

To study the material properties of devices, it is necessary to include millions of sites in a materials science simulation. HQS Qolossal is a Python package that provides access to an efficient tight-binding solver with linear scaling in system size. This enables you to scale up the system size, allowing you to study, for example, semiconductor heterostructures or the effects of larger imperfections in a device. With HQS Qolossal you can directly analyze materials and devices or calculate effective parameters to improve the quality of finite element simulations.

The following quantities are supported:

  • Density of states
  • Trace of the resolvent
  • Green's function
  • Electrical conductivity
  • Expectation value of user-defined operators
  • Static linear response of user-defined operators to user-defined perturbations (e.g. susceptibilities)
  • Spectral function
  • Chemical potential
  • Optical electrical conductivity
  • Carrier density for semiconductors
  • Electron mobility for semiconductors
  • Electron diffusion coefficient for semiconductors
  • Permittivity
  • Normal incidence reflectivity
  • Absorption coefficient