Next Seminar
Chiral nonlocal currents in single layer graphene from orbital valley Hall effects
Tuesday June 21st 2022, 16h – A204
Invited speaker:
Mario Amado
(University of Salamanca)
In this work we report on electrical measurements on single layer graphene Hall-bars encapsulated within hexagonal boron nitride thin films with controlled twisting angle between the layers. The samples have been fabricated by means of a cryo-etching method [1], permitting an unprecedented control of the roughness of the edges. The whole structure was placed onto a thin graphite back gate, preventing dopants or trapped charges arising from the standard semiconductor substrates [2].
We have carried out an exhaustive study of the electrical response at different temperatures when an in-to-out-of-plane external magnetic field has been exerted with special attention to the possible effects arising due to the Moiré pattern. Local and non-local signals are presented and a striking chiral behavior at low magnetic fields of the nonlocal currents resulting from a charge carrier-valley coupling is found, in stark contrast with previous results of similar structures at different twisting angles [3]. Orbital valley Hall effect [4,5] has been found responsible for the presented chiral response with thorough theoretical calculations supporting the experimental results [6].
References
[1] V. Clericò, J. A. Delgado-Notario, M. Saiz-Bretín, A. V. Malyshev, Y. M. Meziani, P. Hidalgo, B. Méndez, M. Amado, F. Domínguez-Adame, and E. Diez, Scientific Reports, 9 (2019) 13572
[2] A.A. Zibrov, C. Kometter, H. Zhou, E. M. Spanton, T. Taniguchi, K. Watanabe, M. P. Zaletel and A. F. Young, Nature. 549 (2017) 360
[3] A. Aharon-Steinberg, A. Marguerite, D. J. Perello, K. Bagani, T. Holder, Y. Myasoedov, L. S. Levitov. A. K. Geim, and E. Zeldoz, Nature 593 (2021) 528
[4] S. Bhowal and G. Vignale, Physical Review B. 103 (2021) 195309
[5] S. Roche, S. R. Power, B. K. Nikolić, J. H. García, and A.-P. Jauho, Journal of Physics: Materials 5 (2022) 021001
[6] J. Salvador-Sánchez et al. arXiv:2206.04565.
Upcoming seminars
Past seminars
Werner Wegscheider (ETH-Zurich)
Danijela Marcovic (UMR-Thales)
Mathieu Delbecq (LPENS)
Jorge Vallejo-Bustamante (LPS)
Liam Farrar (University of St. Andrews)
Christophe Mora (Universite de Paris)
Francois Parmentier (SPEC)
Herve Aubin (C2N)
Michael Manfra (Purdue University)
Banan Kerdi (LNCMI-Toulouse)
Abhishek Juyal (Neel Institute)
Arthur Marguerite (College de France)
Kamran Behnia (ESPCI)
Pierre Capiod (Debye institute for Nanomaterials)
Audrey Bienfait (ENS-Lyon)
Sebastien Toussain (UCL)
David Goldhaber-Gordon (Stanford)
Javad Shabani (NYU)
Olivier Maillet (Aalto)
Mitali Banerjee (EPFL)
Anais Dreau (L2C)
Klaus Ensslin (ETH- Zurich)
Xavier Waintal (CEA- Grenoble)
Gwendal Feve (LPENS)
Shuoying Yang (MPI-Halle)
Yann Gallais (MPQ)
Carles Altimiras (CEA - Saclay)
Alexandra Palacio- Morales ( LPS)
Everton Arrighi (Neel Institute)
