Ferroelectric control of valleytronic nonvolatile storage in HfCl2/Sc2CO2 heterostructure

Abstract

Valleytronics, utilizing the valley degree of freedom in electrons, has potential for advancing the next-generation nonvolatile storage. However, practical implementation remains challenging due to the limited control over valleytronic properties. Here, we propose ferroelectric HfCl2/Sc2CO2 van der Waals heterostructure as a platform to overcome these limitations, enabling tunable and nonvolatile valleytronic behaviors. Our findings show that the electric polarization state of the Sc2CO2 monolayer governs the electronic properties of heterostructures. Positive polarization induces a direct gap at the valleys, enabling valleytronic functionality for excitation and readout via circularly polarized light, while negative polarization results in an indirect-gap, suppressing valleytronic behavior. Moreover, our transport simulations further demonstrate a polarization-dependent ferroelectric p-i-n junction with 8 nm possesses a maximum tunnel electroresistance (TER) ratio of 1.60 × 108% at a bias of 0.5 eV. These results provide insights into ferroelectric-controlled valleytronic transitions and position the HfCl2/Sc2CO2 heterostructure as a promising candidate for energy-efficient valleytronic memory and nonvolatile storage applications.