Current-induced control of the polarization state in a polar metal based heterostructure SnSe/WTe${}_2$

Abstract

The concept of a polar metal proposes new approach of current-induced polarization control for ferroelectrics. We fabricate SnSe/WTe${}_2$ heterostructure to experimentally investigate charge transport between two ferroelectric van der Waals materials with different polarization directions. WTe${}_2$ is a polar metal with out-of-plane ferroelectric polarization, while SnSe ferroelectric semiconductor is polarized in-plane, so one should expect complicated polarization structure at the SnSe/WTe${}_2$ interface. We study $dI/dV(V)$ curves, which demonstrate sharp symmetric drop to zero $dI/dV$ differential conductance at some threshold bias voltages $\pm V_{th}$, which are nearly symmetric in respect to the bias sign. While the gate electric field is too small to noticeably affect the carrier concentration, the positive and negative threshold positions are sensitive to the gate voltage. Also, SnSe/WTe${}_2$ heterostructure shows re-entrant transition to the low-conductive $dI/dV=0$ state for abrupt change of the bias voltage even below the threshold values. This behavior can not be observed for single SnSe or WTe${}_2$ flakes, so we interpret it as a result of the SnSe/WTe${}_2$ interface coupling. In this case, some threshold value of the electric field at the SnSe/WTe${}_2$ interface is enough to drive 90${}^{\circ }$ change of the initial SnSe in-plane polarization in the overlap region. The polarization mismatch leads to the significant interface resistance contribution, analogously to the scattering of the charge carriers on the domain walls. Thus, we demonstrate polarization state control by electron transport through the SnSe/WTe${}_2$ interface.

References in corpus (14)

• Stacking-engineered ferroelectricity in bilayer boron nitride
• A Ferroelectric Semiconductor Field-Effect Transistor
• Microscopic manipulation of ferroelectric domains in SnSe monolayers at room temperature
• Strain-Based Room-Temperature Non-Volatile MoTe${}_2$ Ferroelectric Phase Change Transistor
• `Ferroelectric' Metals Reexamined: Fundamental Mechanisms and Design Considerations for New Materials
• Colloquium: Physical properties of group-IV monochalcogenide monolayers
• Prediction of a native ferroelectric metal
• Design of a multifunctional polar metal via first-principles high-throughput structure screening
• Signature of Fermi arc surface states in Andreev reflection at the WTe${}_2$ Weyl semimetal surface
• Multivalued current-phase relationship in a.c. Josephson effect for a three-dimensional Weyl semimetal WTe${}_2$
• Switching ferroelectricity in SnSe across diffusionless martensitic phase transition
• Band gap reconstruction at the interface between black phosphorus and a gold electrode
• Evidence of the ferroelectric polarization in charge transport through WTe${}_2$ Weyl semimetal surface
• Thermoelectric response as a tool to observe electrocaloric effect in a thin conducting ferroelectric SnSe flake