# Electrical transport properties of polar heterointerface between KTaO3 and SrTiO3

## TL;DR

This study investigates the electrical transport properties of a polar heterointerface between KTaO3 and SrTiO3, revealing unexpected negative charge carriers and providing insights into the doping mechanisms at perovskite oxide interfaces.

## Contribution

It demonstrates the electrical conductivity and negative charge carriers in KTaO3/SrTiO3 heterointerfaces, challenging previous assumptions about hole doping based on formal valences.

## Key findings

- Electrical conductivity observed similar to electron-doped heterointerfaces.
- Hall measurements indicate negative charge carriers.
- Results suggest doping mechanisms differ from formal valence expectations.

## Abstract

Electrical transport of a polar heterointerface between two insulating perovskites, KTaO3 and SrTiO3, is studied. It is formed between a thin KTaO3 film deposited on a top of TiO2- terminated (100) SrTiO3 substrate. The resulting (KO)1-(TiO2)0 heterointerface is expected to be hole-doped according to formal valences of K (1+) and Ti (4+). We observed electrical conductivity and mobility in the KTaO3/SrTiO3 similar to values measured earlier in electron-doped LaAlO3/SrTiO3 heterointerfaces. However, the sign of the charge carriers in KTaO3/SrTiO3 obtained from the Hall measurements is negative. The result is an important clue to the true origin of the doping at perovskite oxide hetero-interfaces.