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Condensed Matter > Strongly Correlated Electrons
Title: Quantum phase transition at non-zero doping in a random $t$-$J$ model
(Submitted on 11 Dec 2020 (v1), last revised 3 Apr 2021 (this version, v2))
Abstract: We present exact diagonalization results on finite clusters of a $t$-$J$ model of spin-1/2 electrons 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 $p=0$ extends to a metallic spin glass phase up to a transition $p=p_c \approx 1/3$. The dynamic spin susceptibility shows signatures of the spectrum of the Sachdev-Ye-Kitaev models near $p_c$. We also find signs of the phase transition in the entropy, entanglement entropy and compressibility, all of which exhibit a maximum near $p_c$. The electron energy distribution function in the metallic phase is consistent with a disordered extension of the Luttinger-volume Fermi surface for $p>p_c$, while this breaks down for $p<p_c$.
Submission history
From: Henry Shackleton [view email][v1] Fri, 11 Dec 2020 19:00:05 GMT (1636kb,D)
[v2] Sat, 3 Apr 2021 22:12:49 GMT (1851kb,D)
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