Terahertz Nonlinear Hall Rectifiers Based on Spin-Polarized 1T-CoTe 2 .

The zero magnetic-field nonlinear Hall effect (NLHE) refers to the second-order transverse current induced by an applied alternating electric field; it indicates the topological properties of inversion-breaking crystals. Despite several studies on the NLHE induced by the Berry-curvature dipole in Weyl semimetals, the direct current conversion by rectification is limited to very low driving frequencies and cryogenic temperatures. The nonlinear photoresponse generated by the NLHE at room temperature can be useful for numerous applications in communication, sensing, and photodetection across a high bandwidth. In this study, we report observations of the second-order NLHE in type-II Dirac semimetal CoTe2 under time-reversal symmetry. This was determined by the disorder-induced extrinsic contribution on the broken-inversion-symmetry surface and room temperature terahertz rectification without the need of semiconductor junctions or bias voltage. We show that remarkable photoresponsivity over 0.1 A W -1 , a response time of approximately 710 ns, and a mean noise equivalent power of 1 pW Hz -1/2 can be achieved at room temperature. Our results open a new pathway for low-energy photon harvesting via nonlinear rectification induced by the NLHE in strongly spin-orbit coupled and inversion-breaking systems, promising a considerable impact in the field of infrared/terahertz photonics. This article is protected by copyright. All rights reserved.