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arXiv · 2503.09954

Evidence of Momentum Space Condensation in Rhombohedral Hexalayer Graphene

Erin Morissette·Peiyu Qin·K. Watanabe·T. Taniguchi·J. I. A. Li
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Abstract

Spontaneous symmetry breaking provides a powerful window into the nature of underlying electronic orders. In strongly correlated systems, multiple symmetry-breaking orders can arise simultaneously. and their interplay generates an intricate landscape of quantum phases that has remained a central focus of condensed-matter research. In this work, we report a previously unidentified electronic phase in rhombohedral hexalayer graphene, distinguished by the simultaneous breaking of rotational, time-reversal, and inversion symmetries. Broken rotational symmetry is evidenced through anisotropic transport in angle-resolved measurements, while the onset of both the anomalous Hall effect and the nonlinear Hall effect signals the breaking of time-reversal and inversion symmetries. These combined signatures reveal an emergent order consistent with momentum-space condensation, a theoretically anticipated phenomenon realized here experimentally for the first time. This mechanism establishes a natural framework for understanding a broader class of correlated phases known to emerge from the flat bands of two-dimensional materials.

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Erin Morissette, Peiyu Qin, K. Watanabe, T. Taniguchi, J. I. A. Li. 2025-03-13. Evidence of Momentum Space Condensation in Rhombohedral Hexalayer Graphene. https://arxiv.org/abs/2503.09954

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