Year: 2026
Type: preprint
Abstract: Chiral superconductors break orbital time-reversal symmetry and may host topological quasiparticles with non-Abelian statistics. In rhombohedral graphene, superconductivity develops from a spin-valley-polarized quarter-metal (QM) parent state and features unique magnetic hysteresis of resistance that indicates orbital time-reversal-symmetry-breaking. Exploring and controlling the full spin-valley flavors of such superconductivity could enable novel superconducting and topological devices, but have remained unexplored. Here we report transport measurements on rhombohedral hexalayer graphene (R6G), which reveal a new superconducting state (SCH) that is induced by an out-of-plane magnetic field, in addition to chiral superconductivity (CSC) similar to those observed in thinner layers. This SCH state emerges above 0.8 T, persists up to 1.6 T and can be switched on/off by magnetic field $H_\perp$, carrier density $n$, and gate displacement field $D$. Quantum oscillations and anomalous Hall measurements show that SCH stems from a field-induced quarter-metal (QM$'$) parent phase, which carries orbital magnetization opposite to that of the zero-field QM. Across the full $(n, D, H_\perp)$ parameter space, superconductivity can be realized from all four spin-valley isospin flavors, establishing a switchable chiral-superconductor quartet in R6G. We interpret the parent-state switching as arising from competition between a Kane-Mele-like spin-valley splitting and magnetic-field coupling to spin-valley-dependent magnetic moments. Our work establishes rhombohedral graphene as a multi-knob platform for different isospin-polarized superconductivities, which enables programmable superconducting networks with possible Majorana modes along domain walls.
Source: arXiv (Cornell University)
Authors: Hua, Zhenqi, Ye, Shenyong, Pattanakanvijit, Phatthanon, Shi, Gang, Han, Tonghang, Aitken, Emily, Yang, Jixiang, Seo, Junseok, Liu, Haoyang, Hao, Ran, Xiao, Kaitai, Guo, Jiaxing, Phong, Vo Tien, Watanabe, Kenji, Taniguchi, Takashi, Huang, Chunli, Lewandowski, Cyprian, Ju, Long, Xiong, Peng, Lu, Zhengguang
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, Florida State University, National High Magnetic Field Laboratory, Ministry of Education, Culture, Sports, Science and Technology, Japan Society for the Promotion of Science, Division of Materials Research, High Magnetic Field Laboratory, Chinese Academy of Sciences
Awards: G1019936685, G227226897, G2442584775, CAREER: Electronic and optical phenomena in moire materials beyond the flat-band paradigm, G3193174607, G3854390519, G4162329948, G4806815962, G5122654266, Charge-Spin Conversions and Nonreciprocal Transport in Chiral Materials, G6671297155, National High Magnetic Field Laboratory Renewal 2023-2027, G742574937, G8152425740, Synthesis of high quality single crystals for sience of Boron Nitride, G898758523
OpenAlex ID: W7167677425
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