APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session D40: 2D Materials: Ferroic Behavior
3:00 PM–6:00 PM,
Monday, March 6, 2023
Room: Room 232
Sponsoring
Unit:
DMP
Chair: Yang Liu; Salvador Barraza-Lopez, University of Arkansas
Abstract: D40.00002 : Ferroelectricity-driven inhomogeneity and giant nonlocality in Graphene/twisted WSe2 heterostructure
3:36 PM–3:48 PM
Abstract
Presenter:
Rahul Debnath
(INDIAN INSTITUTE OF SCIENCE)
Author:
Rahul Debnath
(INDIAN INSTITUTE OF SCIENCE)
The artificial moiré superlattices have extended our design space by allowing two atomically thin layers to be rotated at a desired twist angle to form a moiré pattern that modifies the electronic band structure of the system. Unlike twisted bilayer graphene, where the flat bands occur only near the magic angle of 1.10 due to delicate competition between the hybridization energy and the kinetic energy; twisted bilayer TMDC offers a range of twist angles, where the hybridization energy and the highly commensurate domains are varied with the moiré wavelength. However, unlike graphene, TMDC materials show a massive contact resistance. To overcome this issue, we used graphene as a sensing layer to probe the electronic effects of the underlying twisted TMDC structure on monolayer graphene. Here, we report the observation resistance features on either side of the graphene's Dirac point, which can be tuned further by applying a transverse electric field. The appearance of multiple resistance peaks can be explained by the coexistence of the MX/XM domains of twisted WSe2 having opposite polarization that can be filliped by applying a vertical electric field, which indicates the likely signature of ferroelectricity. We quantitatively characterize the hysteretic ferroelectric gating (coming from the twisted WSe2 between the bottom gate and the graphene) using the reference of an independent background doping (hBN Top gate) provided by normal dielectric gating. We also observe the electric field tunability of the nonlocal resistance, which cannot be explained by the classical ohmic contribution. In our device, due to the proximity of graphene to the ferroelectric twisted WSe2, non-zero Berry Curvature could emerge in graphene by breaking the inversion symmetry of the lattice globally. We further explore the magnetotransport properties of the system and find that the magnetoresistance of the sample increases with an in-plane magnetic field. Our device design not only combines the individual characteristics of the 2D materials but also opens up a new possibility to study the exotic physical properties absent in the parent compounds.