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Enhanced superconducting correlations in the Emery model and its connections to strange metallic transport and normal state coherence

Sijia Zhao, Rong Zhang, Wen O. Wang, Jixun K. Ding, Tianyi Liu, Brian Moritz, Edwin W. Huang, Thomas P. Devereaux

TL;DR

The study investigates whether explicit inclusion of oxygen in cuprate models enhances superconducting tendencies and normal-state coherence. Using numerically exact determinant quantum Monte Carlo (DQMC) to simulate the two-dimensional three-band Emery model, the authors compare its transport and pairing behavior to the single-band Hubbard model, computing the $d$-wave pair-field susceptibility $P_d$ and extracting DC resistivity via optical conductivity with MaxEnt. They find that while both models show $T$-linear resistivity at high temperatures, the Emery model develops a pronounced low-temperature curvature signaling a crossover to more coherent transport, accompanied by a rapid growth of $P_d$ below a crossover temperature around $T \,\sim\,0.4~\text{eV}$. The results suggest a link between normal-state coherence and superconducting fluctuations, with oxygen degrees of freedom reducing scattering and enhancing pairing tendencies, thereby providing a potential bridge between strange-metal transport and high-$T_c$ superconductivity in cuprates. This highlights the importance of multi-orbital physics for understanding superconductivity in strongly correlated materials and offers a quantitative connection between transport and pairing phenomena.

Abstract

Numerical evidence for superconductivity in the single-band Hubbard model is elusive or ambiguous despite extensive study, raising the question of whether the single-band Hubbard model is a faithful low energy effective model for cuprates, and whether explicitly including the oxygen ions will recover the properties necessary for superconducting transition. Here we show, by using numerically exact determinant quantum Monte Carlo (DQMC) simulations of the doped two-dimensional three-band Emery model, that while the single-band model exhibits strikingly T-linear transport behavior, the three-band model shows a low temperature resistivity curvature indicating a crossover to a more metallic transport regime. Evidence has also been found in thermodynamic and superconducting measurements, which suggests that some degree of coherence in transport might be necessary for the high-temperature superconductivity in cuprates, further implying a possible connection between superconducting and transport behaviors.

Enhanced superconducting correlations in the Emery model and its connections to strange metallic transport and normal state coherence

TL;DR

The study investigates whether explicit inclusion of oxygen in cuprate models enhances superconducting tendencies and normal-state coherence. Using numerically exact determinant quantum Monte Carlo (DQMC) to simulate the two-dimensional three-band Emery model, the authors compare its transport and pairing behavior to the single-band Hubbard model, computing the -wave pair-field susceptibility and extracting DC resistivity via optical conductivity with MaxEnt. They find that while both models show -linear resistivity at high temperatures, the Emery model develops a pronounced low-temperature curvature signaling a crossover to more coherent transport, accompanied by a rapid growth of below a crossover temperature around . The results suggest a link between normal-state coherence and superconducting fluctuations, with oxygen degrees of freedom reducing scattering and enhancing pairing tendencies, thereby providing a potential bridge between strange-metal transport and high- superconductivity in cuprates. This highlights the importance of multi-orbital physics for understanding superconductivity in strongly correlated materials and offers a quantitative connection between transport and pairing phenomena.

Abstract

Numerical evidence for superconductivity in the single-band Hubbard model is elusive or ambiguous despite extensive study, raising the question of whether the single-band Hubbard model is a faithful low energy effective model for cuprates, and whether explicitly including the oxygen ions will recover the properties necessary for superconducting transition. Here we show, by using numerically exact determinant quantum Monte Carlo (DQMC) simulations of the doped two-dimensional three-band Emery model, that while the single-band model exhibits strikingly T-linear transport behavior, the three-band model shows a low temperature resistivity curvature indicating a crossover to a more metallic transport regime. Evidence has also been found in thermodynamic and superconducting measurements, which suggests that some degree of coherence in transport might be necessary for the high-temperature superconductivity in cuprates, further implying a possible connection between superconducting and transport behaviors.

Paper Structure

This paper contains 1 section, 2 equations, 3 figures.

Table of Contents

  1. acknowledgments

Figures (3)

  • Figure 1: Temperature dependent pair-field susceptibility comparison between the three-band Emery (A-B) and single-band Hubbard (C-D) models for different hole doping concentrations $p$. (A, C) Inverse $d$-wave pair-field susceptibility $P^{-1}_d$ as a function of temperature. (B, D) Slopes of inverse pair-field susceptibility $\partial(P_d^{-1})/\partial T$ for the data shown in (A, C), normalized against their respective values at $T=2~e$V.
  • Figure 2: Optical conductivity in the Emery model obtained through DQMC and MaxEnt. Data are obtained at various inverse temperatures up to $\beta=7.5~e\text{V}^{-1}$ and the hole doping $p$ away from half filling. The insets in (A) and (C) are zoomed in on the details of the Mott gap and the Drude peak.
  • Figure 3: DC resistivity $\bm{\rho}$, compressibility $\bm{\chi}$ and diffusivity $\bm{D}$ for three-band ((A),(C),(E)) and single-band models ((B),(D),(F)).