AICON: A program for calculating thermal conductivity quickly and accurately

Abstract AICON (Ab Initio Conductivities) is a program written in Python for computing lattice thermal conductivity of crystalline bulk materials using the modified Debye–Callaway model. Building upon the traditional Debye–Callaway theory, the modified model obtains the lattice thermal conductivity by averaging the contributions from acoustic and optical branches based on their specific heat. The only inputs of this program are the phonon spectrum, phonon velocity and Gruneisen parameter, all of which can be calculated using third-party ab initio packages, making the method fully parameter-free. This leads to a fast and accurate evaluation and enables high-throughput calculations of lattice thermal conductivity even in large and complex systems. In addition, this program calculates the specific heat and phonon relaxation times for different scattering processes, which will be beneficial for understanding the phonon transfer behavior. Program summary Program Title: AICON Program Files doi: http://dx.doi.org/10.17632/s9b8y8t92c.1 Licensing provisions: GNU General public license 3 Programming language: Python3 External routines/libraries: Numpy, Scipy, spglib, pymatgen Nature of problem: The calculation of lattice thermal conductivity from first principles with an anharmonic approximation requires a large number of calculations to construct the third-order force constants matrix, which could be prohibitively long time. Solution method: Modified Debye–Callaway model, where only the phonon spectrum, phonon velocity and Gruneisen parameter are needed. The acoustic branch and optic branch are both considered to obtain the final lattice thermal conductivity.