Bipolar conduction and giant positive magnetoresistance in doped metallic titanium oxide heterostructures

TL;DR

This study demonstrates that doping titanium oxide with deuterium induces bipolar conduction and results in a giant positive magnetoresistance, revealing new electronic properties in a conventional material.

Contribution

It reports the first observation of bipolar conduction and giant magnetoresistance in D-doped Ti oxide, highlighting a novel way to modify electronic phases in existing materials.

Findings

Bipolar conduction observed in D-doped TiOx films.

Giant positive magnetoresistance up to 900% at 6 T.

Enhanced electron and hole mobilities after doping.

Abstract

Empowering conventional materials with unexpected magnetoelectric properties is appealing to the multi-functionalization of existing devices and the exploration of future electronics. Recently, owing to its unique effect in modulating a matter's properties, ultra-small dopants, e.g. H, D, and Li, attract enormous attention in creating emergent functionalities, such as superconductivity, and metal-insulator transition. Here, we report an observation of bipolar conduction accompanied by a giant positive magnetoresistance in D-doped metallic Ti oxide (TiOxDy) films. To overcome the challenges in intercalating the D into a crystalline oxide, a series of TiOxDy were formed by sequentially doping Ti with D and surface/interface oxidation. Intriguingly, while the electron mobility of the TiOxDy increases by an order of magnitude larger after doping, the emergent holes also exhibit high mobility. Moreover, the bipolar conduction induces a giant magnetoresistance up to 900% at 6 T, which is ~6 times higher than its conventional phase. Our study paves a way to empower conventional materials in existing electronics and induce novel electronic phases.