Abstract

Unconventional superconductors exhibit multiple broken symmetries and exceed the range of the Bardeen-Cooper-Schrieffer theory. Here we report transport measurements of rhombohedral tetralayer and pentalayer graphene, where a spectrum of superconductivities in a clean limit are observed. Three of them (SC₂-4) show highly unusual enhancements by magnetic fields: SC₂ is strengthened by an in-plane field; SC₃ is boosted by a small out-of-plane field; SC₄ is induced by an in-plane field. All these superconductors are robust against an in-plane field up to 8.5 Tesla, exceeding the Pauli limit of conventional superconductors by tens of times. A separate R₄G/WSe₂ device reveals additional superconducting states induced by proximitized spin-orbit coupling.

Abstract

Unconventional superconductors exhibit multiple broken symmetries and exceed the range of the Bardeen-Cooper-Schrieffer theory. Here we report transport measurements of rhombohedral tetralayer and pentalayer graphene, where a spectrum of superconductivities in a clean limit are observed. Three of them (SC₂-4) show highly unusual enhancements by magnetic fields: SC₂ is strengthened by an in-plane field; SC₃ is boosted by a small out-of-plane field; SC₄ is induced by an in-plane field. All these superconductors are robust against an in-plane field up to 8.5 Tesla, exceeding the Pauli limit of conventional superconductors by tens of times. A separate R₄G/WSe₂ device reveals additional superconducting states induced by proximitized spin-orbit coupling.

Abstract

Unconventional superconductors exhibit multiple broken symmetries and exceed the range of the Bardeen-Cooper-Schrieffer theory. Here we report transport measurements of rhombohedral tetralayer and pentalayer graphene, where a spectrum of superconductivities in a clean limit are observed. Three of them (SC₂-4) show highly unusual enhancements by magnetic fields: SC₂ is strengthened by an in-plane field; SC₃ is boosted by a small out-of-plane field; SC₄ is induced by an in-plane field. All these superconductors are robust against an in-plane field up to 8.5 Tesla, exceeding the Pauli limit of conventional superconductors by tens of times. A separate R₄G/WSe₂ device reveals additional superconducting states induced by proximitized spin-orbit coupling.

Abstract

Unconventional superconductors exhibit multiple broken symmetries and exceed the range of the Bardeen-Cooper-Schrieffer theory. Here we report transport measurements of rhombohedral tetralayer and pentalayer graphene, where a spectrum of superconductivities in a clean limit are observed. Three of them (SC₂-4) show highly unusual enhancements by magnetic fields: SC₂ is strengthened by an in-plane field; SC₃ is boosted by a small out-of-plane field; SC₄ is induced by an in-plane field. All these superconductors are robust against an in-plane field up to 8.5 Tesla, exceeding the Pauli limit of conventional superconductors by tens of times. A separate R₄G/WSe₂ device reveals additional superconducting states induced by proximitized spin-orbit coupling.