Year: 2026
Type: preprint
Abstract: Electronic states with coexisting Wigner-crystal order can sometimes exhibit a quantum Hall effect over a finite range of electron densities---i.e., exhibit ``extended'' quantum Hall (QH) plateaus in the absence of disorder. Such an extended quantum Hall state can then compete with other QH states over the same density range, allowing a first-order thermal transition between them. Here, we analyze several settings in which the entropy associated with Goldstone modes (e.g., magnons or phonons) or soft gapped modes (e.g., magnetoroton) drives a finite-temperature transition between competing QH regimes. Applying this framework to moiré rhombohedral graphene, we argue that a soft magnetoroton in a fractional quantum anomalous Hall state provides a plausible bulk mechanism for the observed thermal evolution from an extended integer QH to a fractional QH regime.
Source: arXiv (Cornell University)
Authors: Kim, Kyung-Su, Kivelson, Steven A.
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7213403749