The discovery of Tc ~ 80 K superconductivity in pressurized La3Ni2O7 has launched a new platform to study high-temperature superconductivity. Using non-perturbative dynamic cluster approximation quantum Monte Carlo calculations, we characterize the magnetic and superconducting pairing behavior of a realistic bilayer two-orbital Hubbard-Hund model of this system that describes the relevant Ni eg states with physically relevant interaction strengths. We find a leading s± superconducting instability in this model at a temperature T ~ 100 K close to the experimentally observed Tc. Analyzing the orbital and spatial structure of the effective pairing interaction giving rise to this state reveals that the interaction predominantly acts between local interlayer pairs of the <InlineEquation ID="IEq1"> <EquationSource Format="TEX">${d}_{3{z}^{2}-{r}^{2}}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mrow> <mi>d</mi> </mrow> <mrow> <mn>3</mn> <msup> <mrow> <mi>z</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msup> <mo>-</mo> <msup> <mrow> <mi>r</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msup> </mrow> </msub> </math></EquationSource> </InlineEquation> orbital. By correlating the strength of the interaction with that of the magnetic spin fluctuations we show that it is driven by strong interlayer spin-fluctuations arising from the <InlineEquation ID="IEq2"> <EquationSource Format="TEX">${d}_{3{z}^{2}-{r}^{2}}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mrow> <mi>d</mi> </mrow> <mrow> <mn>3</mn> <msup> <mrow> <mi>z</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msup> <mo>-</mo> <msup> <mrow> <mi>r</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msup> </mrow> </msub> </math></EquationSource> </InlineEquation> orbital. These results provide first-time non-perturbative evidence supporting the picture that a simple single-orbital bilayer Hubbard model for the Ni <InlineEquation ID="IEq3"> <EquationSource Format="TEX">${d}_{3{z}^{2}-{r}^{2}}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mrow> <mi>d</mi> </mrow> <mrow> <mn>3</mn> <msup> <mrow> <mi>z</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msup> <mo>-</mo> <msup> <mrow> <mi>r</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msup> </mrow> </msub> </math></EquationSource> </InlineEquation> orbital provides an excellent low-energy effective description of the superconducting behavior of La3Ni2O7.

Interlayer pairing in bilayer nickelates

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2026年1月22日

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Thomas A. Maier,
Peter Doak,
Ling-Fang Lin,
Yang Zhang,
Adriana Moreo,
Elbio Dagotto

摘要

The discovery of T_c ~ 80 K superconductivity in pressurized La₃Ni₂O₇ has launched a new platform to study high-temperature superconductivity. Using non-perturbative dynamic cluster approximation quantum Monte Carlo calculations, we characterize the magnetic and superconducting pairing behavior of a realistic bilayer two-orbital Hubbard-Hund model of this system that describes the relevant Ni e_g states with physically relevant interaction strengths. We find a leading s^± superconducting instability in this model at a temperature T ~ 100 K close to the experimentally observed T_c. Analyzing the orbital and spatial structure of the effective pairing interaction giving rise to this state reveals that the interaction predominantly acts between local interlayer pairs of the ${d}_{3{z}^{2}-{r}^{2}}$ $d_{3 z^{2} - r^{2}}$ orbital. By correlating the strength of the interaction with that of the magnetic spin fluctuations we show that it is driven by strong interlayer spin-fluctuations arising from the ${d}_{3{z}^{2}-{r}^{2}}$ $d_{3 z^{2} - r^{2}}$ orbital. These results provide first-time non-perturbative evidence supporting the picture that a simple single-orbital bilayer Hubbard model for the Ni ${d}_{3{z}^{2}-{r}^{2}}$ $d_{3 z^{2} - r^{2}}$ orbital provides an excellent low-energy effective description of the superconducting behavior of La₃Ni₂O₇.