2018/04/30 by Julen Ibañez-Azpiroz, Stepan S. Tsirkin, Ivo Souza · 2 citations
Chemistry · Mathematics · Physics and Astronomy · #Advanced Chemical Physics Studies #Chemistry #Diagonal #Electronic structure #GaN-based semiconductor devices and materials #Hamiltonian (control theory) #Mathematical analysis #Mathematics #Operator (biology) #Physics #Quantum and electron transport phenomena #Quantum mechanics #Subspace topology #Tight binding #Wannier function #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.97.245143
published as Phys. Rev. B 97, 245143 (2018) · 13 pages, 7 figures
openalex created_date 2018/04/24 · openalex publication_date 2018/06/26 · arxiv created 2018/06/28 · arxiv updated 2018/06/29 · openalex updated_date 2026/08/05
We describe and implement a first-principles algorithm based on maximally localized Wannier functions for calculating the shift-current response of piezoelectric crystals in the independent-particle approximation. The proposed algorithm presents several advantages over existing ones, including full gauge invariance, low computational cost, and a correct treatment of the optical matrix elements with nonlocal pseudopotentials. Band-truncation errors are avoided by a careful formulation of k\ifmmode⋅\else\textperiodcentered\fip perturbation theory within the subspace of wannierized bands. The needed ingredients are the matrix elements of the Hamiltonian and of the position operator in the Wannier basis, which are readily available at the end of the wannierization step. If the off-diagonal matrix elements of the position operator are discarded, our expressions reduce to the ones that have been used in recent tight-binding calculations of the shift current. We find that this ``diagonal'' approximation can introduce sizable errors, highlighting the importance of carefully embedding the tight-binding model in real space for an accurate description of the charge transfer that gives rise to the shift current.