• 文献标题:   Highly tunable junctions and non-local Josephson effect in magic-angle graphene tunnelling devices
  • 文献类型:   Article
  • 作  者:   RODANLEGRAIN D, CAO Y, PARK JM, DE LA BARRERA SC, RANDERIA MT, WATANABE K, TANIGUCHI T, JARILLOHERRERO P
  • 作者关键词:  
  • 出版物名称:   NATURE NANOTECHNOLOGY
  • ISSN:   1748-3387 EI 1748-3395
  • 通讯作者地址:  
  • 被引频次:   41
  • DOI:   10.1038/s41565-021-00894-4 EA MAY 2021
  • 出版年:   2021

▎ 摘  要

Magic-angle twisted bilayer graphene exhibits a wide range of phases, such as metal, insulator and superconductor states. Now local electrostatic gating devices made from this two-dimensional material platform enable highly tunable Josephson junctions, edge tunnelling spectroscopy and single-electron transistor operation. Magic-angle twisted bilayer graphene (MATBG) has recently emerged as a highly tunable two-dimensional material platform exhibiting a wide range of phases, such as metal, insulator and superconductor states. Local electrostatic control over these phases may enable the creation of versatile quantum devices that were previously not achievable in other single-material platforms. Here we engineer Josephson junctions and tunnelling transistors in MATBG, solely defined by electrostatic gates. Our multi-gated device geometry offers independent control of the weak link, barriers and tunnelling electrodes. These purely two-dimensional MATBG Josephson junctions exhibit non-local electrodynamics in a magnetic field, in agreement with the Pearl theory for ultrathin superconductors. Utilizing the intrinsic bandgaps of MATBG, we also demonstrate monolithic edge tunnelling spectroscopy within the same MATBG devices and measure the energy spectrum of MATBG in the superconducting phase. Furthermore, by inducing a double-barrier geometry, the devices can be operated as a single-electron transistor, exhibiting Coulomb blockade. With versatile functionality encompassed within a single material, these MATBG tunnelling devices may find applications in graphene-based tunable superconducting qubits, on-chip superconducting circuits and electromagnetic sensing.