Significant Second-Harmonic Generation and Bulk Photovoltaic Effect in Trigonal Selenium and Tellurium Chains

TL;DR

This paper investigates the nonlinear optical properties of one-dimensional selenium and tellurium chains, revealing their exceptional second-harmonic generation and photovoltaic responses, which surpass many bulk materials and have potential applications in energy and optoelectronics.

Contribution

The study provides first-principles calculations demonstrating that 1D Se and Te exhibit significantly enhanced nonlinear optical responses compared to their bulk forms and other materials.

Findings

1D Se has a second-harmonic generation coefficient up to 7 times larger than GaN.

1D Te exhibits NLO susceptibility exceeding bulk GaN by 5 times.

Te chains show large shift current responses, twice as high as BaTiO3.

Abstract

One-dimensional selenium and tellurium crystalize in helical chainlike structures and thus exhibit fascinating properties. By performing first-principles calculations, we have researched the linear and nonlinear optical (NLO) properties of 1D Se and Te, and find that both systems exhibit pronounced NLO responses. In particular, 1D Se is found to possess large second-harmonic generation coefficient being up to 7 times larger than that of GaN, and even is several times larger than that of the bulk counterpart. On the other hand, 1D Te also produces significant NLO susceptibility which exceeds the bulk GaN by 5 times. Furthermore, 1D Te is shown to possess prominent linear electro-optic coefficient rxxx(0). Particularly, Te chain exhibits large shift current response and the maximum is more than the maximal photovoltaic responses obtained from BaTiO3 by 2 times. Therefore, 1D Se and Te may find potential applications in solar energy conversion, electro-optical switches, and so on. Finally, much stronger NLO effects of 1D Se and Te are attributed to their one-dimensional structures with high anisotropy, strong covalent bonding and lone-pair electrons. These findings will contribute to the further study in experiments and search for excellent materials with large NLO effects.