Property analysis and simulation package for materials (PASP) and its applications to 2D ferroic materials

We have developed a software package, namely, PASP (Property Analysis and Simulation Package for materials), to analyze the structural, electronic, magnetic, and thermodynamic properties of complex condensed matter systems. Our package integrates several functionalities including group theory analysis, global structure searching methods, tight-binding approach, machine learning algorithms, effective Hamiltonian methods, Monte Carlo simulation, and spin-lattice dynamic simulation methods. In conjunction with first-principles calculations, PASP has been successfully applied to diverse 2D ferroic systems. For example, we propose a general theory for bilayer stacking ferroelectricity, find that there may exist high-order spin interactions and Kitaev interactions in 2D magnets, propose a novel mechanism that realizes the electric-field switching of magnetic topological charge in a controllable and reversible fashion.