Engineering Berry curvature dipole and nonlinear Hall currents in CdTe monolayers for emerging memory applications

Abstract

We report a first-principles study elucidating the valleytronic and nonlinear transport phenomena in buckled hexagonal MX (M = Zn, Cd; X = S, Se, Te) monolayers. Our findings establish that ZnTe and CdTe monolayers exhibit a pronounced, intrinsic Berry curvature concentrated at the K and K′ valleys, arising from their robust spin–orbit coupling and inherent inversion symmetry breaking. Crucially, we uncover a significant, non-zero Berry curvature dipole (BCD) in these systems, providing compelling evidence for a robust nonlinear Hall effect under time-reversal-symmetric conditions. Such an intrinsic second-order response is highly desirable for advanced electronic functionalities. Furthermore, we demonstrate that uniaxial strain serves as an effective and versatile tool, activating the tunability of BCD components. This enables unprecedented strain-mediated control over the magnitude and vectorial direction of second-order nonlinear currents along distinct in-plane orientations. These findings position CdTe monolayers as compelling candidates for strain-tunable nonlinear transport, culminating in a proposal for a multistate neuromorphic memory device architecture that exploits vectorial current modulation.