Programme

I.5 -- Invited, VCTP-48

Date: Tuesday, 1 August 2023

Time: 10:30 - 11:10

Density functional theory calculations on the prototypical low-dimensional charge-density-wave system, In atomic wires on Si(111)

Hanchul Kim

Department of Materials Physics and Institute of Advanced Materials and Systems, Sookmyung Women’s University, Seoul 04310, Korea

Metal-adsorbed semiconductors have attracted much interest in surface science because they provide valuable platforms for studying exotic low-dimensional phenomena. Indium (In) atomic wires self-assembled on the Si(111) surface is a prototypical quasi-one-dimensional (quasi-1D) system undergoing a structural phase transition from the room-temperature (RT) 4$\times$1 to the low-temperature (LT) 8$\times$2 structure at ~120K, which is known to be a charge density wave (CDW) condensation. This structural phase transition is known to be accompanied by an electronic metal-insulator transition. This presentation will discuss a comprehensive set of density functional theory calculations for the Si(111)In system. First, the atomic structure of the RT phase and its electronic structure will be discussed. Secondly, the atomic and electronic structures of the LT-8$\times$2 CDW phase will be described in conjunction with the microscopic mechanism of phase transition. Then, I will describe the defect-related phenomena focusing on the effects on the CDW phase transition. Finally, I will deliver an understanding of topological solitons in the LT-8$\times$2 phase. The results from atomic-resolution scanning tunneling microscopy experiments will be frequently introduced throughout the presentation to verify the theoretical predictions.

Presenter: Kim Hanchul