Normal and superconducting properties of La$_3$Ni$_2$O$_7$

TL;DR

This review summarizes current experimental and theoretical research on La$_3$Ni$_2$O$_7$, a high-temperature superconductor, focusing on its structural, electronic, and magnetic properties under high pressure, and discusses future challenges.

Contribution

It provides a comprehensive overview of experimental findings and theoretical models for La$_3$Ni$_2$O$_7$, highlighting recent progress and ongoing challenges in understanding its superconductivity.

Findings

Experimental synthesis and characterization of La$_3$Ni$_2$O$_7$ under high pressure.

Theoretical models explaining electronic structure and pairing mechanisms.

Identification of challenges in sample quality and measurement techniques.

Abstract

This review provides a comprehensive overview of current research on the structural, electronic, and magnetic characteristics of the recently discovered high-temperature superconductor La$_3$Ni$_2$O$_7$ under high pressures. We present the experimental results for synthesizing and characterizing this material, derived from measurements of transport, thermodynamics, and various spectroscopic techniques, and discuss their physical implications. We also explore theoretical models proposed to describe the electronic structures and superconducting pairing symmetry in La$_3$Ni$_2$O$_7$, highlighting the intricate interplay between electronic correlations and magnetic interactions. Despite these advances, challenges remain in growing high-quality samples free of extrinsic phases and oxygen deficiencies and in developing reliable measurement tools for determining diamagnetism and other physical quantities under high pressures. Further investigations in these areas are essential to deepening our understanding of the physical properties of La$_3$Ni$_2$O$_7$ and unlocking its superconducting pairing mechanism.