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Spontaneous Time-Reversal Symmetry Breaking at Individual Grain Boundaries in Graphene

Hsieh, K and Kochat, V and Biswas, T and Tiwary, CS and Mishra, A and Ramalingam, G and Jayaraman, A and Chattopadhyay, K and Raghavan, S and Jain, M and Ghosh, A (2021) Spontaneous Time-Reversal Symmetry Breaking at Individual Grain Boundaries in Graphene. In: Physical Review Letters, 126 (20).

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Official URL: https://doi.org/10.1103/PhysRevLett.126.206803


Graphene grain boundaries (GBs) have attracted interest for their ability to host nearly dispersionless electronic bands and magnetic instabilities. Here, we employ quantum transport and universal conductance fluctuation measurements to experimentally demonstrate a spontaneous breaking of time-reversal symmetry across individual GBs of chemical vapor deposited graphene. While quantum transport across the GBs indicate spin-scattering-induced dephasing and hence formation of local magnetic moments, below T4 K we observe complete lifting of time-reversal symmetry at high carrier densities (n5�1012 cm-2) and low temperature (T2 K). An unprecedented thirtyfold reduction in the universal conductance fluctuation magnitude with increasing doping density further supports the possibility of an emergent frozen magnetic state at the GBs. Our experimental results suggest that realistic GBs of graphene can be a promising resource for new electronic phases and spin-based applications. © 2021 American Physical Society.

Item Type: Journal Article
Publication: Physical Review Letters
Publisher: American Physical Society
Additional Information: The copyright for this article belongs to Authors
Keywords: Electric conductance; Grain boundaries; Magnetic moments; Quantum chemistry; Quantum theory; Temperature, Chemical vapor deposited; Electronic phasis; Frozen magnetic state; Individual grain boundaries; Local magnetic moments; Magnetic instability; Time reversal symmetries; Universal conductance fluctuations, Graphene
Department/Centre: Division of Chemical Sciences > Materials Research Centre
Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Division of Physical & Mathematical Sciences > Physics
Date Deposited: 18 Aug 2021 05:35
Last Modified: 18 Aug 2021 05:35
URI: http://eprints.iisc.ac.in/id/eprint/69168

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