Tunable magnetism of a single-carbon vacancy in graphene

Yu Zhang; Fei Gao; Shiwu Gao; Lin He

doi:10.1016/j.scib.2019.11.023

Tunable magnetism of a single-carbon vacancy in graphene

Sci Bull (Beijing). 2020 Feb 15;65(3):194-200. doi: 10.1016/j.scib.2019.11.023. Epub 2019 Nov 23.

Authors

Yu Zhang¹, Fei Gao², Shiwu Gao³, Lin He⁴

Affiliations

¹ Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, China.
² Computational Science Research Center, ZPark II, Beijing 100193, China.
³ Computational Science Research Center, ZPark II, Beijing 100193, China. Electronic address: swgao@csrc.ac.cn.
⁴ Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, China; State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China. Electronic address: helin@bnu.edu.cn.

PMID: 36659172
DOI: 10.1016/j.scib.2019.11.023

Abstract

Creating a single-carbon vacancy introduces (quasi-)localized states for both σ and π electrons in graphene. Theoretically, interactions between the localized σ electrons and quasilocalized π electrons of a single-carbon vacancy in graphene are predicted to control its magnetism. However, experimentally confirming this prediction through manipulating the interactions remains an outstanding challenge. Here we report the manipulation of magnetism in the vicinity of an individual single-carbon vacancy in graphene by using a scanning tunnelling microscopy (STM) tip. Our spin-polarized STM measurements, complemented by density functional theory calculations, indicate that the interactions between the localized σ and quasilocalized π electrons could split the π electrons into two states with opposite spins even when they are well above the Fermi level. Via the STM tip, we successfully manipulate both the magnitude and direction of magnetic moment of the π electrons with respect to that of the σ electrons. Three different magnetic states of the single-carbon vacancy, exhibiting magnetic moments of about 1.6 μ_B, 0.5 μ_B, and 0 μ_B respectively, are realized in our experiment.

Keywords: Graphene; Magnetic moment; Scanning tunnelling microscopy; Single-carbon vacancy; Tunable magnetism.