Novel interference state by tuning gate in magic-angle twisted bilayer graphene

Lian Wen^1,2*, Kuo-En Chang^1,2, Chiu-Hau Huang^1,2, Ching-Hua Kao^1,2, Yu-Chiang Hsieh^1,2, Shin-Ji Fung^1,2, Jun-Sheng Wu^1,2, Shih-Hsiang Chao^1,2, Tse-Ming Chen^1,2

¹Department of Physics, National Cheng Kung University, Tainan, Taiwan
²Center for Quantum Frontier of Research and Technology, National Cheng Kung University, Tainan, Taiwan

* Presenter:Lian Wen, email:l26094247@gs.ncku.edu.tw

Magic-angle twisted bilayer graphene (MATBG) has recently emerged as a versatile platform that combines metallic, superconducting, magnetic and insulating phases in a single crystal¹. One of the applications by tuning the correlated states in MATBG is the development of Josephson junction (JJ)². It was confirmed that the critical current in JJ can be modified by adjusting the gate of the barrier². As a result, we fabricate MATBG-based superconducting quantum interference device (SQUID) using bubble free transfer technique³, e-beam lithography and conduct electrical measurements. Furthermore, this SQUID can become an asymmetry loop by unmatched critical current with different gate between two JJs⁴. With this advantage, we plan to tune the SQUID into asymmetry and improve its sensitivity under specific magnetic field region⁴. This provides the opportunity for future applications in superconducting electronics⁵ and quantum information technology⁶.

Reference
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Keywords: SQUID, superconductor, Josephson junction, graphene