Generation and control of non-local chiral currents in graphene superlattices by orbital Hall effect
ORAL
Abstract
In this study, we present electrical measurements on single-layer graphene Hall-bars that are encapsulated within hexagonal boron nitride thin films and have a controlled twisting angle between the layers. The samples were fabricated using a cryo-etching method, which allowed us to achieve unprecedented control over the roughness of the edges. The entire structure was placed onto a thin graphite back gate to prevent dopants or trapped charges that can arise from standard semiconductor substrates.
We conducted a comprehensive study of the magnetotransport reponse of the structure at different temperatures, applying an in to-out-of-plane external field and paying special attention to the possible effects arising due to the Moiré pattern.
We present local and non-local signals and report a striking chiral behavior of the nonlocal currents at low magnetic fields resulting from a charge carrier-valley coupling. This behavior is in stark contrast to previous results of similar structures at different twisting angles. The presented chiral response is found to be caused by the orbital valley Hall effect, with thorough theoretical calculations supporting our experimental results.
*Spanish Ministry of Science, Innovation, and Universities Grants PID2019-106820RB-C21/22, PGC2018-094180-B-I00, PID2019-106684GB-I00 / AEI /10.13039/501100011033. FEDER/Junta de Castilla y León Research Grant number SA121P20. Marie SkłodowskaCurie-COFUND USAL4Excellence program (101034371). Ministerio de Universidades (Spain) (PhD contract FPU19/04224). EU Seventh Framework Programme under grant no. 881603 (Graphene Flagship). Severo Ochoa programme (MINECO SEV-2017-0706). Fundação para a Ciência e a Tecnologia and Instituto de Telecomunicações - grant UID/50008/2020 project Sym-Break. Brazilian agency CAPES. MICINN Ramón y Cajal program (Project No. RYC2019-028443-I). Center for Novel Pathways to Quantum Coherence in Materials funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences. JSPS KAKENHI (Grant Numbers 19H05790, 20H00354 and 21H05233). CENTERA Laboratories under the European Regional Development Fund (No. MAB/2018/9).
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Publication:https://arxiv.org/abs/2206.04565
Presenters
Mario Amado
Univ de Salamanca
Authors
Mario Amado
Univ de Salamanca
Juan Salvador-Sánchez
Universtiy of Salamanca
Univ. de Salamanca
Universidad de Salamanca
Luis M Canonico
ICN2
ICN2 - CSIC
Ana Pérez-Rodríguez
University of Salamanca
Univ de Salamanca
Universidad de Salamanca
Tarik P Cysne
Universidade Federal Fluminense
Yuriko C Baba
Univ Complutense
Vito Clericò
University of Salamanca
Univ de Salamanca
Marc Vila
Department of Physics, UC Berkeley and Materials Sciences Division, LBNL
UC Berkeley and LBNL
Daniel Vaquero
Univ de Salamanca
Juan Antonio Delgado-Notario
CENTERA Lab
José Caridad
Univ de Salamanca
Kenji Watanabe
National Institute for Materials Science
NIMS
Research Center for Electronic and Optical Materials, National Institute for Materials Science
Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
National Institute for Material Science
Takashi Taniguchi
Kyoto Univ
National Institute for Materials Science
Research Center for Materials Nanoarchitectonics
Research Center for Materials Nanoarchitectonics, National Institute for Materials Science
National Institute for Materials Sciences
NIMS
International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
National Institute for Material Science
International Center for Materials Nanoarchitectonics, NIMS, Japan
International Center for Materials Nanoarchitectonics, Tsukuba
National Institue for Materials Science
Kyoto University
National Institute of Materials Science
International Center for Materials Nanoarchitectonics and National Institute for Materials Science
