Photonic spin Hall effect of monolayer black phosphorus in the Terahertz region

Jianhui Yu,Hai Lin,Binguo Chen,Zhe Chen,Wenguo Zhu,Huihui Lu,Songqing Yang,Yunhan Luo,Heyuan Guan

doi:10.1515/nanoph-2018-0101

Abstract

Abstract As a two-dimensional (2D) material, black phosphorus (BP) has attracted significant attention owing to exotic physical properties such as low-energy band gap, high carrier mobility, and strong in-plane anisotropy. The striking in-plane anisotropy is a promising candidate for novel light-matter interaction. Here, we investigate the photonic spin Hall effect (PSHE) on a monolayer of BP. Due to the in-plane anisotropic property of BP, the PSHE is accompanied with Goos-Hänchen and Imbert-Fedorov effects, resulting in an asymmetric spin splitting. The asymmetric spin splitting can be flexibly tuned by the angle between the incident plane and the armchair crystalline direction of BP and by the carrier density via a bias voltage. The centroid displacements of two opposite spin components of the reflected beam along directions parallel and perpendicular to the incident plane can be considered as four independent channels for information processing. The potential application in barcode-encryption is proposed and discussed. These findings provide a deeper insight into the spin-orbit interaction in 2D material and thereby facilitate the development of optoelectronic devices in the Terahertz region.

Highlights

Two-dimensional (2D) materials have received a huge amount of interest in recent years due to their exciting physical properties [1,2,3,4]
As a two-dimensional (2D) material, black phosphorus (BP) has attracted significant attention owing to exotic physical properties such as low-energy band gap, high carrier mobility, and strong in-plane anisotropy
The potential application in barcode-encryption is proposed and discussed. These findings provide a deeper insight into the spin-orbit interaction in 2D material and thereby facilitate the development of optoelectronic devices in the Terahertz region

Summary

Introduction

Two-dimensional (2D) materials have received a huge amount of interest in recent years due to their exciting physical properties [1,2,3,4]. In monolayer BP, the phosphorus atoms form a hexagonal lattice with a puckered structure resulting in its in-plane anisotropic property [5, 7]. In 2017, a BP-based wave plate was fabricated, where the polarization-plane rotation per atomic layer reached up to ~0.005° [15]. Lin et al.: Photonic spin Hall effect of monolayer black phosphorus the spin-dependent shifts originated from the PSHE are accompanied by both spin-independent Goos-Hänchen (GH) and Imbert-Fedorov (IF) shifts, resulting in an asymmetric spin splitting of the reflected Gaussian beam in directions both parallel and perpendicular to the plane of incidence [22,23,24]. The modulation of the asymmetric spin splitting by the carrier density in the monolayer BP is studied based on which the potential applications in barcode-encryption is proposed and discussed

Model and theory

Results and discussion

Conclusion