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Publication Detail / Abstract

H. Shackleton, A. Wietek, A, Georges, S. Sachdev

Quantum Phase Transition at Nonzero Doping in a Random t − J Model

published on Physical Review Letters on March 30, 2021
> Full text via publisher
We present exact diagonalization results on finite clusters of a t−J model of spin-1/2electrons with random all-to-all hopping and exchange interactions. We argue that such random models capture qualitatively the strong local correlations needed to describe the cuprates and related compounds, while avoiding lattice space group symmetry breaking orders. The previously known spin glass ordered phase in the insulator at doping = 0 extends to a metallic spin glass phase up to a transition p≈ 1/3. The dynamic spin susceptibility shows signatures of the spectrum of the Sachdev-Ye-Kitaev models near p. We also find signs of the phase transition in the entropy, entanglement entropy, and compressibility, all of which exhibit a maximum near pc. The electron energy distribution function in the metallic phase is consistent with a disordered extension of the Luttinger-volume Fermi surface for p, while this breaks down for p p.
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