Speaker
Description
An accurate first-principles description of the electronic band structure at finite temperatures is the prerequisite to quantitatively predict the electronic and optical properties of real materials. Theoretically, this requires proper consideration of the self-energy contributions from both electron-electron (e-e) and electron-vibration (e-vib) interactions. For the latter, the widely used electron-phonon coupling (EPC) model [1] fails for strongly anharmonic materials. Furthermore, while the self-energy contributions from the two types of interactions are considered separately within the EPC model, they can be treated collectively in a statistical manner [2] by combining the $GW$ method with ab initio molecular dynamics. To realize this approach, a robust and efficient $GW$ implementation for periodic systems is of key importance.
In this poster, we present our recent efforts to implement this approach to study electron self-energy using FHI-aims, an all-electron full-potential framework with compact numeric atom-centered orbitals (NAOs).[3] The one-shot periodic $G_0W_0$ method in FHI-aims is implemented based on the localized resolution-of-identity (RI) technique. [4,5] We first benchmark the performance of our $G_0W_0$ implementation in terms of accuracy and efficiency. We then show that a proper treatment of the dielectric response at long wave-length limit can significantly accelerate the convergence of quasiparticle band gap with respect to k-grids and auxiliary basis sets. Finally, using the band unfolding technique implemented in the NAO framework, we present temperature-dependent electronic band structure of silicon accounting for e-e and e-vib interactions, as a proof of concept.
References
[1] F. Giustino, Electron-phonon interactions from first principles, Rev. Mod. Phys. 89, 015003, 2017; https://doi.org/10.1103/RevModPhys.89.015003
[2]M. Zacharias, M. Scheffler, and C. Carbogno, Fully anharmonic nonperturbative theory of vibronically renormalized electronic band structures, Phys. Rev. B 102, 045126, 2020; https://doi.org/10.1103/PhysRevB.102.045126
[3]V. Blum, R. Gehrke, F. Hanke, P. Havu, V. Havu, X. Ren, K. Reuter, and M. Scheffler, Ab initio molecular simulations with numeric atom-centered orbitals, Comput. Phys. Commun. 180, 2175–2196, 2009; https://doi.org/10.1016/j.cpc.2009.06.022
[4]A. C. Ihrig, J. Wieferink, I. Y. Zhang, M. Ropo, X. Ren, P. Rinke, M. Scheffler, and V. Blum, Accurate localized resolution of identity approach for linear-scaling hybrid density functionals and for many-body perturbation theory, New J. Phys. 17, 093020, 2015; https://doi.org/10.1088/1367-2630/17/9/093020
[5] X. Ren, F. Merz, H. Jiang, Y. Yao, M. Rampp, H. Lederer, V. Blum, and M. Scheffler, All-electron periodic G0W0 implementation with numerical atomic orbital basis functions: Algorithm and benchmarks, Phys. Rev. Materials 5, 013807, 2021; https://doi.org/10.1103/PhysRevMaterials.5.013807
*This project was supported by the NOMAD Center of Excellence (European Union's Horizon 2020 research and innovation program, Grant Agreement No. 951786) and the ERC Advanced Grant TEC1p (European Research Council, Grant Agreement No. 740233)
