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Caltech

IQIM Postdoctoral and Graduate Student Seminar

Friday, November 3, 2023
12:15pm to 1:15pm
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East Bridge 201 (Richard P. Feynman Lecture Hall)
Spin-Orbit Enhanced Superconductivity in Graphene Bilayers
Yiran Zhang, Nadj-Perge group,

Abstract: The flat electronic bands of moiré and crystalline graphene promote a wide variety of correlated ground states, including unconventional superconductivity. In this talk, I will discuss a series of experiments that stabilize and enhance graphene superconductivity through the proximity of spin-orbit coupling (SOC). First, I will present our transport data showing that, by placing twisted bilayer graphene on tungsten diselenide, the superconductivity can be stabilized down to twist angles as small as 0.79 degrees. Importantly, for angles in this range, the correlated insulating states disappear while signatures of interaction remain. Second, I will report our observation that introducing Ising SOC to Bernal bilayer graphene promotes superconductivity with an order of magnitude enhancement in superconducting Tc. Quantum oscillations suggest a broken-symmetry parent state, and In-plane-field response reveals an unusual Pauli-limit violation. Further tuning SOC by interfacial twisting, we map out the onset and Tc of superconductivity, as well as multiple superconducting regions. Our results pave the way for a detailed understanding of unconventional pairing in graphene superconductors and establish a highly tunable and ultra-clean platform for topological quantum processes.

Note: This week's talk begins at 12:15 pm in 201 E. Bridge.

Lunch will be provided, following the talk, on the lawn north of the Bridge Building.

For more information, please contact Marcia Brown by phone at 626-395-4013 or by email at [email protected].