Two-dimensional Stoner transitions beyond mean-field

Zachary M. Raines; Andrey V. Chubukov

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arXiv · 2409.18934

Two-dimensional Stoner transitions beyond mean-field

Zachary M. Raines·Andrey V. Chubukov

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Abstract

We have previously shown that the Stoner instability 2D has unconventional behavior: it is strongly first order but features a susceptibility which diverges at the transition point. Here, we analyze the Stoner transition for two-dimensional systems with spin and valley degrees of freedom, beyond mean field. At low density, we show that in one-valley and isotropic two-valley systems the leading effect beyond mean-field theory is suppression of the Stoner instability. In anisotropic two-valley systems, we show that, for larger anisotropy, the transition remains mean-field-like and retains its unconventional properties. We discuss applications to AlAs quantum wells.

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Zachary M. Raines, Andrey V. Chubukov. 2024-09-27. Two-dimensional Stoner transitions beyond mean-field. https://arxiv.org/abs/2409.18934

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