Bilayer twisting as a mean to isolate connected flat bands in a kagome lattice throughWigner crystallization*

Journal Article · 01 July 2021 · Chinese Physics. B

DOI:https://doi.org/10.1088/1674-1056/abd7d6· OSTI ID:1850826

Wu, Jing; Xie, Yue-E; Chen, Ming-Xing; Yuan, Jia-Ren; Yan, Xiao-Hong; Zhang, Sheng-Bai; Chen, Yuan-Ping

The physics of flat band is novel and rich but difficult to access. In this regard, recently twisting of bilayer van der Waals (vdW)-bounded two-dimensional (2D) materials has attracted much attention, because the reduction of Brillouin zone will eventually lead to a diminishing kinetic energy. Alternatively, one may start with a 2D kagome lattice, which already possesses flat bands at the Fermi level, but unfortunately these bands connect quadratically to other (dispersive) bands, leading to undesirable effects. Here, we propose, by first-principles calculation and tight-binding modeling, that the same bilayer twisting approach can be used to isolate the kagome flat bands. As the starting kinetic energy is already vanishingly small, the interlayer vdW potential is always sufficiently large irrespective of the twisting angle. As such the electronic states in the (connected) flat bands become unstable against a spontaneous Wigner crystallization, which is expected to have interesting interplays with other flat-band phenomena such as novel superconductivity and anomalous quantum Hall effect.

• Research Organization: Rensselaer Polytechnic Inst., Troy, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: SC0002623
• OSTI ID: 1850826
• Journal Information: Chinese Physics. B, Vol. 30, Issue 7; ISSN 1674-1056
• Publisher: IOP Publishing
• Country of Publication: United States
• Language: English

Related Subjects

Physics