The O-M-O triatomic molecule: Basic unit of cuprates & manganates

TL;DR

This paper investigates the O-M-O triatomic molecule as a fundamental unit in cuprates and manganates, analyzing its symmetry, vibrational modes, and electron transport properties relevant to high-temperature superconductivity and colossal magnetoresistance.

Contribution

It provides a detailed group-theoretical analysis and calculates electron hopping energies, highlighting the role of bond polarons in electrical transport within these materials.

Findings

Transport dominated by bond polaron scattering

Two-branch temperature dependence of resistance

Symmetry-dependent vibrational mode limitations

Abstract

The O(oxygen)-M(metal)-O(oxygen) molecule is a basic unit of high-temperature superconducting cuprates and colossal magnetoresistance exhibiting manganates. This molecule can be regarded either as an element of a linear chain or as an ingredient of the corresponding cuprate or manganate lattice. The symmetry of the unit being different in the two approaches, group theory imposes different limitations on conceivable vibrational modes and atomic otbitals that control its transport and optical properties. We now calculate the electron hopping energies along Cu(P0-O(A) bonds, sites for nonlocal electron-vibrational mode coupling. We find the electric transport along the O(A)-Cu(P)-O(A) molecule dominated by scattering from bond polarons which is reflected in the two-branch character of the temperature dependence of its electric resistance.