Interstitial-induced ferromagnetism in a two-dimensional Wigner crystal

Abstract

The two-dimensional Wigner crystal (WC) occurs in the strongly interacting regime ($r_s\gg 1$) of the two-dimensional electron gas (2DEG). The magnetism of a pure WC is determined by tunneling processes that induce multi-spin ring-exchange interactions, resulting in fully polarized ferromagnetism for large enough $r_s$. Recently, Hossain et al. [PNAS 117 (51) 32244-32250] reported the occurrence of a fully polarized ferromagnetic insulator at $r_s\gtrsim 35$ in an AlAs quantum well, but at temperatures orders of magnitude larger than the predicted exchange energies for the pure WC. Here, we analyze the large $r_s$ dynamics of an interstitial defect in the WC, and show that it produces local ferromagnetism with much higher energy scales. Three hopping processes are dominant, which favor a large, fully polarized ferromagnetic polaron. Based on the above results, we speculate concerning the phenomenology of the magnetism near the metal-insulator transition of the 2DEG.

arXiv comment4 pages + references & Supplementary (5 pages), 2+4 figures, 1 table. Minor revision based on comments

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Cited by in corpus (13)

• Observation of an electronic microemulsion phase emerging from a quantum crystal-to-liquid transition
• Probing magnetism in moiré heterostructures with quantum twisting microscopes
• Spin-polarons and ferromagnetism in doped dilute Wigner-Mott insulators
• Nematic metal in a multi-valley electron gas: Variational Monte Carlo analysis and application to AlAs
• Exact Hole-induced Resonating-Valence-Bond Ground State in Certain $U=\infty$ Hubbard Models
• Local noise spectroscopy of Wigner crystals in two-dimensional materials
• Chiral Wigner crystal phases induced by Berry curvature
• Critical gate distance for Wigner crystallization in the two-dimensional electron gas
• Magnetism of the Bilayer Wigner Crystal
• Defect liquids in a weakly imbalanced bilayer Wigner Crystal
• Magnetism from multiparticle ring exchange in moiré Wigner crystals
• Exchange Interactions of a Wigner Crystal in a Magnetic Field and Berry Curvature: Multi-Particle Tunneling through Complex Trajectories
• The exchange coupling of a Wigner dimer