Analysis of charge transfer mechanism on (Ba1-xNdxCuO2+d)2/(CaCuO2)n superconducting superlattices by thermoelectric power measurements

TL;DR

This study uses thermoelectric power measurements to analyze charge transfer in BaNdCuO2+d/CaCuO2 superlattices, revealing uniform charge distribution and effects of doping and disorder on electronic properties.

Contribution

It introduces a precise thermoelectric measurement approach to investigate charge transfer mechanisms in superconducting superlattices, highlighting the effects of doping and structural disorder.

Findings

Charge distributes uniformly among CuO2 planes in Ca-block.

Nd doping affects the metallic character of Ba-block.

Structural disorder impacts charge transfer in n=1 superlattices.

Abstract

We have investigated the charge transfer mechanism in artificial superlattices by Seebeck effect measurements. Such a technique allows a precise determination of the amount of charge transferred on each CuO2 plane. A systematic characterization of thermoelectric power in (BaCuO2+d)2/(CaCuO2)n and (Ba0.9Nd0.1CuO2+d)2/(CaCuO2)n superlattices demonstrates that electrical charge distributes uniformly among the CuO2 planes in the Ca-block. The differences observed in the Seebeck effect behavior between the Nd-doped and undoped superlattices are ascribed to the different metallic character of the Ba-block in the two cases. Finally, the special role of structural disorder in superlattices with n=1 is pointed out by such analysis.