Unconventional Spin Hall Effect in Low Symmetry Semimetal for Large Spin-Orbit Readout Unit*

This study explores the utilization of unconventional spin Hall effects in a new class of 2D materials for advanced spintronic devices beyond CMOS. The crystalline symmetry breaking in few-layer MoTe₂ enables the coexistence of a large spin Hall angle (θ_SH) and extended spin diffusion length (L_S), as well as relaxing the stringent requirement of orthogonality between spin polarization, spin current, and charge current. Our experimental investigation focuses on the characterization of the unconventional spin Hall conductivity ( ) in few-layer MoTe₂, achieved through the deliberate disruption of mirror symmetry in the crystal structure. Our device design, based on the magnetoelectric spin-orbit (MESO) concept, exhibits a large output resistance of . This notable performance is attributed to the long spin diffusion length and high resistivity of the semi-metallic channel, distinguishing it from conventional metallic giant spin Hall effect (GSHE) materials. Furthermore, we observe a linear increase in the device output with increasing temperature and device dimension scaling, leading to a projected value of . This promising result demonstrates a two-order of magnitude improvement over the current MESO device designs with conventional materials.