Fermi surface change and $d$-wave superconductivity in the square lattice Kondo-Heisenberg model

• URL: http://arxiv.org/abs/2606.23799v1
• Date: Mon, 22 Jun 2026 18:00:04 GMT
• Title: Fermi surface change and $d$-wave superconductivity in the square lattice Kondo-Heisenberg model
• Abstract summary: We study the two-dimensional Kondo-Heisenberg model on a square lattice, with the conduction electrons away from half-filling, using neural network quantum states.<n>Our results establish Fermi volume change and unconventional superconductivity as intrinsic features of the two-dimensional Kondo-Heisenberg model.
• Score: 38.80690522643898
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: We study the two-dimensional Kondo-Heisenberg model on a square lattice, with the conduction electrons away from half-filling, using neural network quantum states. Mapping the ground-state phase diagram as a function of the Kondo and Heisenberg couplings, we identify (i) at weak Kondo coupling, antiferromagnetic Néel order with a Fermi surface whose enclosed area counts only the conduction electrons and is insensitive to the Néel order, and (ii) at strong coupling, a heavy Fermi liquid with a Fermi surface whose enclosed area counts both the conduction electrons and the spins. In the crossover between these regimes, we find $d_{x^2-y^2}$ superconductivity, evidenced by off-diagonal long-range order in the pair-pair correlations and a pairing-amplitude dome that coexists with the underlying magnetic phase. Our results establish Fermi volume change and unconventional superconductivity as intrinsic features of the two-dimensional Kondo-Heisenberg model.

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