Localization to delocalization probed by magnetotransport of hBN/graphene/hBN stacks in the ultra-clean regime

Takuya Iwasaki; Satoshi Moriyama; Nurul Fariha Ahmad; Katsuyoshi Komatsu; Kenji Watanabe; Takashi Taniguchi; Yutaka Wakayama; Abdul Manaf Hashim; Yoshifumi Morita; Shu Nakaharai

doi:10.1038/s41598-021-98266-4

Localization to delocalization probed by magnetotransport of hBN/graphene/hBN stacks in the ultra-clean regime

Sci Rep. 2021 Sep 22;11(1):18845. doi: 10.1038/s41598-021-98266-4.

Authors

Takuya Iwasaki^{1

2}, Satoshi Moriyama^{3

4}, Nurul Fariha Ahmad^{5

6}, Katsuyoshi Komatsu⁵, Kenji Watanabe⁷, Takashi Taniguchi⁵, Yutaka Wakayama⁵, Abdul Manaf Hashim⁶, Yoshifumi Morita⁸, Shu Nakaharai⁹

Affiliations

¹ International Center for Young Scientists, National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, 305-0044, Japan. IWASAKI.Takuya@nims.go.jp.
² International Center for Materials Nanoarchitectonics, NIMS, Tsukuba, Ibaraki, 305-0044, Japan. IWASAKI.Takuya@nims.go.jp.
³ International Center for Materials Nanoarchitectonics, NIMS, Tsukuba, Ibaraki, 305-0044, Japan. moriyama.satoshi@mail.dendai.ac.jp.
⁴ Department of Electrical and Electronic Engineering, Tokyo Denki University, 5 Senju-Asahi-cho, Adachi-ku, Tokyo, 120-8551, Japan. moriyama.satoshi@mail.dendai.ac.jp.
⁵ International Center for Materials Nanoarchitectonics, NIMS, Tsukuba, Ibaraki, 305-0044, Japan.
⁶ Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100, Kuala Lumpur, Malaysia.
⁷ Research Center for Functional Materials, NIMS, Tsukuba, Ibaraki, 305-0044, Japan.
⁸ Faculty of Engineering, Gunma University, Kiryu, Gunma, 376-8515, Japan. morita@gunma-u.ac.jp.
⁹ International Center for Materials Nanoarchitectonics, NIMS, Tsukuba, Ibaraki, 305-0044, Japan. NAKAHARAI.Shu@nims.go.jp.

Abstract

We report on magnetotransport in a high-quality graphene device, which is based on monolayer graphene (Gr) encapsulated by hexagonal boron nitride (hBN) layers, i.e., hBN/Gr/hBN stacks. In the vicinity of the Dirac point, a negative magnetoconductance is observed for high temperatures > ~ 40 K, whereas it becomes positive for low temperatures ≤ ~ 40 K, which implies an interplay of quantum interferences in Dirac materials. The elastic scattering mechanism in hBN/Gr/hBN stacks contrasts with that of conventional graphene on SiO₂, and our ultra-clean graphene device shows nonzero magnetoconductance for high temperatures of up to 300 K.

Abstract

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