Current-induced control of the polarization state in a polar-metal–based heterostructure SnSe/WTe 2
Year: 2022
Type: article
Abstract: The concept of a polar metal suggests a new approach to 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 curves, which demonstrate sharp symmetric drop to zero differential conductance at some threshold bias voltages , which are nearly symmetric with 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 state for abrupt change of the bias voltage even below the threshold values. This behavior cannot 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 a 90° 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.
Source: Europhysics Letters (EPL)
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
Funder: Russian Science Foundation
Award: G2060193335
OpenAlex ID: W4225919885