Indirect electric field doping of the CuO2 planes of the cuprate NdBa2Cu3O7 superconductor

TL;DR

This study investigates how electric fields induce doping in cuprate superconductors, revealing that holes are generated in CuO chains and transferred to CuO2 planes, influenced by the interface and charge reservoir properties.

Contribution

It provides direct spectroscopic evidence of charge transfer mechanisms in field-effect doping of cuprates, highlighting the role of the charge reservoir and interface effects.

Findings

Holes are created at CuO chains under electric field.

Charge transfer from chains to CuO2 planes occurs during doping.

Electronic properties of the interface influence doping efficiency.

Abstract

The mechanism of field-effect doping in the "123" high critical temperature superconductors (HTS) has been investigated by x-ray absorption spectroscopy in the presence of an electric field. We demonstrate that holes are created at the CuO chains of the charge reservoir and that field-effect doping of the CuO2 planes occurs by charge transfer, from the chains to the planes, of a fraction of the overall induced holes. The electronic properties of the charge reservoir and of the dielectric/HTS interface determine the electric field doping of the CuO2 planes