  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.
