Large positive magnetoresistance in photocarrier doping potassium tantalites in the extreme quantum limit

TL;DR

This study demonstrates large, non-saturating positive magnetoresistance in photocarrier-doped KTaO3 crystals at low temperatures and high magnetic fields, attributed to the extreme quantum limit where electrons occupy only the lowest Landau level.

Contribution

It reveals the occurrence of quantum magnetoresistance in KTaO3 in the extreme quantum limit, a novel observation for this material family.

Findings

Magnetoresistance increased by 433% at 10 K and 12 T.

Positive, linear, non-saturating magnetoresistance observed.

Vanishing Hall coefficient indicates electrons occupy only the lowest Landau level.

Abstract

We report on a high-field magnetotransport study of KTaO3 single crystals. This material is a promising candidate to study in the extreme quantum limit (EQL). By photocarrier doping with 360 nm light, we have observed a significant positive, non-saturating, and linear magnetoresistance at low temperatures accompanied by a vanishing Hall coefficient. When cooled down to 10 K and subjected to a magnetic field of 12 T, the value of magnetoresistance of KTaO3 (100) is increased by as much as 433%. Such behavior can be attributed to all electrons occupying only the lowest Landau level in the EQL. In this state, a quantum magnetoresistance is produced. This result provides novel insights into the next generation of magnetic devices based on complex materials and adds a new family of materials with positive magnetoresistance.