journal article·2023-08-22Open access

Gate-Tunable Renormalization of Spin-Correlated Flat-Band States and Bandgap in a 2D Magnetic Insulator

Pin Lyu, Joachim Sødequist, Xiaoyu Sheng, Zhizhan Qiu, Anton Tadich, Qile Li, Mark T. Edmonds, Meng Zhao, Jesús Redondo, Martin Švec, Peng Song, Thomas Olsen, Jiong Lu

ACS Nano· Volume 17· Issue 16

Abstract

Emergent quantum phenomena in two-dimensional van der Waal (vdW) magnets are largely governed by the interplay between exchange and Coulomb interactions. The ability to precisely tune the Coulomb interaction enables the control of spin-correlated flat-band states, band gap, and unconventional magnetism in such strongly correlated materials. Here, we demonstrate a gate-tunable renormalization of spin-correlated flat-band states and bandgap in magnetic chromium tribromide (CrBr 3 ) monolayers grown on graphene. Our gate-dependent scanning tunneling spectroscopy (STS) studies reveal that the interflat-band spacing and bandgap of CrBr 3 can be continuously tuned by 120 and 240 meV, respectively, via electrostatic injection of carriers into the hybrid CrBr 3 /graphene system. This can be attributed to the self-screening of CrBr 3 arising from the gate-induced carriers injected into CrBr 3, which dominates over the weakened remote screening of the graphene substrate due to the decreased carrier density in graphene. Precise tuning of the spin-correlated flat-band states and bandgap in 2D magnets via electrostatic modulation of Coulomb interactions not only provides effective strategies for optimizing the spin transport channels but also may exert a crucial influence on the exchange energy and spin-wave gap, which could raise the critical temperature for magnetic order.
Source: openalex_inverted_index · Quality: baseline

Research context

OpenAlex topics: Graphene research and applications · 2D Materials and Applications · Topological Materials and Phenomena

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

Affiliations

Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore

Institute for Functional Intelligent Materials, National University of Singapore, Singapore 117544, Singapore

Department of Physics, Computational Atomic-Scale Materials Design (CAMD), Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark

ARC Centre for Future Low Energy Electronics Technologies, Monash University, Clayton, Victoria 3800, Australia

Australian Synchrotron, Clayton, Victoria 3168, Australia

School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia

Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore

Institute of Physics of the Czech Academy of Sciences, Cukrovarnicka 10, 162 00 Prague 6, Czech Republic

Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, 180 00 Prague, Czech Republic

School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798,Singapore

School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798,Singapore

Funding

Agency for Science, Technology and Research · Ministry of Education - Singapore · Villum Fonden

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