Multiple k-Point Nonadiabatic Molecular Dynamics for Ultrafast Excitations in Periodic Systems: The Example of Photoexcited Silicon
Author(s): Zheng, F (Zheng, Fan); Wang, LW (Wang, Lin-wang)
Source: PHYSICAL REVIEW LETTERS?Volume: 131?Issue: 15??Article Number: 156302??DOI: 10.1103/PhysRevLett.131.156302??Published: OCT 10 2023?
Abstract: With the rapid development of ultrafast experimental techniques for the research of carrier dynamics in solid-state systems, a microscopic understanding of the related phenomena, particularly a first-principle calculation, is highly desirable. Nonadiabatic molecular dynamics (NAMD) offers a real-time direct simulation of the carrier transfer or carrier thermalization. However, when applied to a periodic supercell, there is no cross-k-point transitions during the NAMD simulation. This often leads to a significant underestimation of the transition rate with the single-k-point band structure in a supercell. In this work, based on the surface hopping scheme used for NAMD, we propose a practical method to enable the cross-k transitions for a periodic system. We demonstrate our formalism by showing that the hot electron thermalization process by the multi-k-point NAMD in a small silicon supercell is equivalent to such simulation in a large supercell with a single Gamma point. The simulated hot carrier thermalization process of the bulk silicon is compared with the recent ultrafast experiments, which shows excellent agreements. We have also demonstrated our method for the hot carrier coolings in the amorphous silicons and the GaAlAs2 solid solutions with the various cation distributions.
Accession Number: WOS:001102939300005
PubMed ID: 37897744
Author Identifiers:
Author?Web of Science ResearcherID?????ORCID Number
Zheng, Fan???????0000-0002-6497-6198
Wang, Lin-Wang??????0000-0001-7061-2692
ISSN: 0031-9007
eISSN: 1079-7114
