Superfluid stiffness of twisted multilayer graphene superconductors
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arXiv
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| Auteurs principaux: | , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866913398281732096 |
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| author | Banerjee, Abhishek Hao, Zeyu Kreidel, Mary Ledwith, Patrick Phinney, Isabelle Park, Jeong Min Zimmerman, Andrew M. Watanabe, Kenji Taniguchi, Takashi Westervelt, Robert M Jarillo-Herrero, Pablo Volkov, Pavel A. Vishwanath, Ashvin Fong, Kin Chung Kim, Philip |
| author_facet | Banerjee, Abhishek Hao, Zeyu Kreidel, Mary Ledwith, Patrick Phinney, Isabelle Park, Jeong Min Zimmerman, Andrew M. Watanabe, Kenji Taniguchi, Takashi Westervelt, Robert M Jarillo-Herrero, Pablo Volkov, Pavel A. Vishwanath, Ashvin Fong, Kin Chung Kim, Philip |
| contents | The robustness of the macroscopic quantum nature of a superconductor can be characterized by the superfluid stiffness, $ρ_s$, a quantity that describes the energy required to vary the phase of the macroscopic quantum wave function. In unconventional superconductors, such as cuprates, the low-temperature behavior of $ρ_s$ drastically differs from that of conventional superconductors due to quasiparticle excitations from gapless points (nodes) in momentum space. Intensive research on the recently discovered magic-angle twisted graphene family has revealed, in addition to superconducting states, strongly correlated electronic states associated with spontaneously broken symmetries, inviting the study of $ρ_s$ to uncover the potentially unconventional nature of its superconductivity. Here we report the measurement of $ρ_s$ in magic-angle twisted trilayer graphene (TTG), revealing unconventional nodal-gap superconductivity. Utilizing radio-frequency reflectometry techniques to measure the kinetic inductive response of superconducting TTG coupled to a microwave resonator, we find a linear temperature dependence of $ρ_s$ at low temperatures and nonlinear Meissner effects in the current bias dependence, both indicating nodal structures in the superconducting order parameter. Furthermore, the doping dependence shows a linear correlation between the zero temperature $ρ_s$ and the superconducting transition temperature $T_c$, reminiscent of Uemura's relation in cuprates, suggesting phase-coherence-limited superconductivity. Our results provide strong evidence for nodal superconductivity in TTG and put strong constraints on the mechanisms of these graphene-based superconductors. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2406_13742 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Superfluid stiffness of twisted multilayer graphene superconductors Banerjee, Abhishek Hao, Zeyu Kreidel, Mary Ledwith, Patrick Phinney, Isabelle Park, Jeong Min Zimmerman, Andrew M. Watanabe, Kenji Taniguchi, Takashi Westervelt, Robert M Jarillo-Herrero, Pablo Volkov, Pavel A. Vishwanath, Ashvin Fong, Kin Chung Kim, Philip Superconductivity Mesoscale and Nanoscale Physics Strongly Correlated Electrons Quantum Physics The robustness of the macroscopic quantum nature of a superconductor can be characterized by the superfluid stiffness, $ρ_s$, a quantity that describes the energy required to vary the phase of the macroscopic quantum wave function. In unconventional superconductors, such as cuprates, the low-temperature behavior of $ρ_s$ drastically differs from that of conventional superconductors due to quasiparticle excitations from gapless points (nodes) in momentum space. Intensive research on the recently discovered magic-angle twisted graphene family has revealed, in addition to superconducting states, strongly correlated electronic states associated with spontaneously broken symmetries, inviting the study of $ρ_s$ to uncover the potentially unconventional nature of its superconductivity. Here we report the measurement of $ρ_s$ in magic-angle twisted trilayer graphene (TTG), revealing unconventional nodal-gap superconductivity. Utilizing radio-frequency reflectometry techniques to measure the kinetic inductive response of superconducting TTG coupled to a microwave resonator, we find a linear temperature dependence of $ρ_s$ at low temperatures and nonlinear Meissner effects in the current bias dependence, both indicating nodal structures in the superconducting order parameter. Furthermore, the doping dependence shows a linear correlation between the zero temperature $ρ_s$ and the superconducting transition temperature $T_c$, reminiscent of Uemura's relation in cuprates, suggesting phase-coherence-limited superconductivity. Our results provide strong evidence for nodal superconductivity in TTG and put strong constraints on the mechanisms of these graphene-based superconductors. |
| title | Superfluid stiffness of twisted multilayer graphene superconductors |
| topic | Superconductivity Mesoscale and Nanoscale Physics Strongly Correlated Electrons Quantum Physics |
| url | https://arxiv.org/abs/2406.13742 |