Polaron Effects on Superexchange Interaction: Isotope Shifts of $T_N$, $T_C$, and $T^*$ in Layered Copper Oxides

TL;DR

This paper presents a theoretical analysis of how polaron effects influence superexchange interactions in layered copper oxides, explaining isotope shifts in key transition temperatures such as $T_N$, $T_C$, and $T^*$.

Contribution

It derives a compact expression for superexchange coupling considering polaron effects, providing insights into isotope shifts in layered cuprates.

Findings

Polaron effects significantly impact superexchange interactions.

The derived expression explains isotope shifts in $T_N$, $T_C$, and $T^*$.

The analysis offers a unified understanding of isotope effects in cuprate superconductors.

Abstract

A compact expression has been obtained for the superexchange coupling of magnetic ions via intermediate anions with regard to polaron effects at both magnetic ions and intermediate anions. This expression is used to analyze the main features of the behavior of isotope shifts for temperatures of three types in layered cuprates: the Neel temperatures ($T_N$), critical temperatures of transitions to a superconducting state ($T_C$), and characteristic temperatures of the pseudogap in the normal state ($T^*$).