Exciton Dispersion and Dipole Orientation in 2D Monochalcogenides

Vo Khuong Dien^1*, Ping-yuan Lo¹, Guan-Hao Peng¹, Wei-Hua Li¹, Shun-Jen Cheng¹

¹Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan

* Presenter:Vo Khuong Dien, email:vokhuongdien@nycu.edu.tw

Two-dimensional (2D) materials exhibit strong excitonic effects due to reduced dielectric screening and enhanced Coulomb interactions, resulting in intriguing many-body phenomena. This study theoretically investigates the exciton fine structure and dipole orientation in 2D monochalcogenides by solving the Bethe-Salpeter equation (BSE) within a density-functional-theory (DFT) framework. Our results reveal a unique exciton dipole orientation and a nonanalytic exciton dispersion near the light cone. We connect these characteristics to exciton emission, highlighting the crucial role of excitonic effects in these materials and their potential for promising applications.

Keywords: 2D monochalcogenides , Exciton, Dipole Orientation