Ab-initio description of hole localization and Zhang-Rice singlets in one-dimensional doped cuprates

TL;DR

This paper provides the first ab-initio band-theory-based analysis of Zhang-Rice singlets in a one-dimensional doped cuprate, revealing how hole doping induces charge localization and phase transitions.

Contribution

It introduces a novel ab-initio approach to describe spin-compensated polarons and Zhang-Rice singlets in a doped cuprate, linking electronic structure to phase behavior.

Findings

Identification of Zhang-Rice singlets above a doping threshold

Transition from insulator to metal to insulator with doping

Charge localization leads to phase changes in the material

Abstract

We present the first ab-initio band-theory-based description of spin-compensated polarons (known as Zhang-Rice singlets) in a hole-doped cuprate, specifically one-dimensional Ca_{2+x} Y_{2-x} Cu_5 O_10. Zhang-Rice singlets are many-particle configurations relevant to the exotic behavior of hole-doped cuprates, stemming from spontaneous charge localization. They appear in our case-study material above a threshold doping, successively turning the insulating undoped antiferromagnet into a gap insulator, a singlet-rich metallic paramagnet, and finally, a singlet-saturated insulating diamagnet.