Ambient-pressure Dirac electron system in the quasi-two-dimensional molecular conductor α−(BETS)2I3

• Kitou, Shunsuke

• Tsumuraya, Takao

• Sawahata, Hikaru

• Ishii, Fumiyuki

• Hiraki, Ko-ichi

• Nakamura, Toshikazu

• Katayama, Naoyuki

• Sawa, Hiroshi

Bibliographic Information

Other Title

• Ambient-pressure Dirac electron system in the quasi-two-dimensional molecular conductor <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>α</mml:mi><mml:mtext>−</mml:mtext><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mi>BETS</mml:mi><mml:mo>)</mml:mo></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">I</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>

Abstract

We investigated the precise crystal structures and electronic states of a quasi-two-dimensional molecular conductor α−(BETS)2I3 at ambient pressure. The electronic resistivity of this molecular solid shows metal-to-insulator (MI) crossover behavior at TMI=50K. Our x-ray diffraction and 13C nuclear magnetic resonance experiments revealed that α−(BETS)2I3 maintains the inversion symmetry below TMI. First-principles calculations found a pair of anisotropic Dirac cones at a general k point, with the degenerate contact points at the Fermi level. The origin of the insulating state in this system is a small energy gap of ∼2meV opened by the spin-orbit interaction. The Z2 topological invariants indicate that this system is a weak topological insulator. Our results suggest that α−(BETS)2I3 is a promising material for studying the bulk Dirac electron system in two dimensions.

Journal

• Physical Review B

  Physical Review B 103 035135-, 2021-01-15

  American Physical Society

Details

• CRID: 1050852714961996032
• NII Article ID: 120007163652
• DOI: 10.1103/physrevb.103.035135
• ISSN: 24699969
• ISSN: 24699950
• HANDLE: 2237/0002001515
• Web Site: https://nagoya.repo.nii.ac.jp/records/2001515
• Web Site: https://link.aps.org/article/10.1103/PhysRevB.103.035135
• Web Site: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevB.103.035135/fulltext
• Text Lang: en
• Article Type: journal article
• Data Source:
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