Regensburg 2025 – scientific programme
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O: Fachverband Oberflächenphysik
O 85: New Methods: Theory
O 85.9: Talk
Thursday, March 20, 2025, 12:30–12:45, H25
Full periodic real-time TD-DFTB implementation for solids and low-dimensional materials — •Carlos R. Lien-Medrano1, Franco P. Bonafé2, Matías Berdakín3, Cristián G. Sánchez4, and Michael Sentef1,2 — 1University of Bremen, Bremen, Germany — 2MPSD, Hamburg, Germany — 3Universidad Nacional de Córdoba, Córdoba, Argentina — 4Universidad Nacioanl de Cuyo, Mendoza, Argentina
The current real-time time-dependent density functional tight-binding (TD-DFTB) dynamics implementation in the DFTB+ package [1] employs the length gauge of the electric field. In this work, we introduce an implementation of the vector potential within the velocity gauge framework. This approach enables the extension of real-time dynamics simulations to periodic systems along arbitrary spatial directions, making it applicable to photo-induced dynamical processes in bulk, low-dimensional materials, and surfaces. To demonstrate its potential, we present proof-of-concept applications, including the inhomogeneous optical absorption around the K point in graphene, light absorption in bulk materials, and prospective applications in the field of valleytronics.
[1] Hourahine, B., et al. (2020). DFTB+, a software package for efficient approximate density functional theory based atomistic simulations. The Journal of Chemical Physics, 152(12), 124101.
Keywords: DFTB; TD-DFTB; 2D Materials; Excited States