Linear resistivity at van Hove singularities in twisted bilayer WSe2

• 成果类型: Article
• 署名作者: Wei, Lingnan; Xu, Qiaoling; He, Yangchen; Li, Qingxin; Huang, Yan; Zhu, Wang; Watanabe, Kenji; Taniguchi, Takashi; Claassen, Martin; Rhodes, Daniel A.; Kennesh, Dante M.; Xian, Lede; Rubio, Angel; Wang, Lei
• 署名单位: Nanjing University; Songshan Lake Materials Laboratory; Sichuan Normal University; University of Wisconsin System; University of Wisconsin Madison; National Institute for Materials Science; National Institute for Materials Science; University of Pennsylvania; RWTH Aachen University; Max Planck Society; Simons Foundation; Flatiron Institute; Collaborative Innovation Center of Advanced Microstructures (CICAM); Nanjing University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-12828
• DOI: 10.1073/pnas.2321665121
• 发表日期: 2024-04-16
• 关键词: high-temperature superconductivity; TRANSITION; BEHAVIOR

摘要

Different mechanisms driving a linear temperature dependence of the resistivity rho - T at van Hove singularities (VHSs) or metal- insulator transitions when doping a Mott insulator are being debated intensively with competing theoretical proposals. We experimentally investigate this using the exceptional tunability of twisted bilayer (TB) WSe2 by tracking the parameter regions where linear-in- Tresistivity is found in dependency of displacement fields, filling, and magnetic fields. We find that even when the VHSs are tuned rather far away from the half-filling point and the Mott insulating transition is absent, the T- linear resistivity persists at the VHSs. When doping away from the VHSs, the T- linear behavior quickly transitions into a Fermi liquid behavior with a T2 relation. No apparent dependency of the linear-in- T resistivity, besides a rather strong change of prefactor, is found when applying displacement fields as long as the filling is tuned to the VHSs, including D - 0.28 V/nm where a high-order VHS is expected. Intriguingly, such non-Fermi liquid linear-in- T resistivity persists even when magnetic fields break the spin- degeneracy of the VHSs at which point two linear in Tregions emerge, for each of the split VHSs separately. This points to a mechanism of enhanced scattering at generic VHSs rather than only at high-order VHSs or by a quantum critical point during a Mott transition. Our findings provide insights into the many-body consequences arising out of VHSs, especially the non-Fermi liquid behavior found in moir & eacute; materials.