TBPLaS: a Tight-Binding Package for Large-scale Simulation

  TBPLaS is an open-source software package for the accurate simulation of physical systems with arbitrary geometry and dimensionality utilizing the tight-binding (TB) theory. It has an intuitive object-oriented Python application interface (API) and Cython/Fortran extensions for the performance-critical parts, ensuring both flexibility and efficiency. Under the hood, numerical calculations are mainly performed by both exact diagonalization and the tight-binding propagation method (TBPM) without diagonalization. Especially, the TBPM is based on the numerical solution of the time-dependent Schrödinger equation, achieving linear scaling with system size in both memory and CPU costs. Consequently, TBPLaS provides a numerically cheap approach to calculate the electronic, optical, plasmon and transport properties of large tight-binding models with billions of atomic orbitals. Current capabilities of TBPLaS include the calculations of band structure, density of states, local density of states, quasi-eigenstates, optical conductivity, electrical conductivity, Hall conductivity, polarization function, dielectric function, plasmon dispersion, carrier mobility and velocity, localization length and free path, ℤ₂topological invariant, wave-packet propagation, etc. All the properties can be obtained with only a few lines of code. TBPLaS is a powerful tool to tackle complex systems, for example, graphene with vacancies, twisted multilayer graphene, twisted multilayer transition metal dichalcogenides, graphene-boron nitride heterostructures, dodecagonal bilayer graphene quasicrystals and fractals.