Anisotropic Behavior of Excitons in Single Crystal α-SnS

Van Long Le; Do Duc Cuong; Hoang Tung Nguyen; Xuan Au Nguyen; Bogyu Kim; Kyujin Kim; Wonjun Lee; Soon Cheol Hong; Tae Jung Kim; Young Dong Kim

arXiv · 2007.03449

Anisotropic Behavior of Excitons in Single Crystal α-SnS

Van Long Le·Do Duc Cuong·Hoang Tung Nguyen·Xuan Au Nguyen·Bogyu Kim·Kyujin Kim·Wonjun Lee·Soon Cheol Hong·Tae Jung Kim·Young Dong Kim

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Abstract

We investigate analytically the anisotropic dielectric properties of single crystal α-SnS near the fundamental absorption edge by considering atomic orbitals. Most striking is the excitonic feature in the armchair- (b-) axis direction, which is particularly prominent at low temperatures. To determine the origin of this anisotropy, we perform first-principles calculations using the GW0 Bethe-Salpeter equation (BSE) including the electron-hole interaction. The results show that the anisotropic dielectric characteristics are a direct result of the natural anisotropy of p orbitals. In particular, this dominant excitonic feature originates from the py orbital at the saddle point in the Γ-Y region.

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Van Long Le, Do Duc Cuong, Hoang Tung Nguyen, Xuan Au Nguyen, Bogyu Kim, Kyujin Kim, Wonjun Lee, Soon Cheol Hong, Tae Jung Kim, Young Dong Kim. 2020-07-07. Anisotropic Behavior of Excitons in Single Crystal α-SnS. https://arxiv.org/abs/2007.03449

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