Complex oxide thin films have attracted significant attention due to a wealth of physical phenomena, such as Mott transitions arising from strong interactions in d-bands. Moreover, the physical phenomena observed in these materials exhibit sensitivities, which are not found in conventional semiconductors and give rise to abrupt changes in their electrical properties depending on the means of control. The richness of electronic phases and unique functionalities of complex oxides are suitable for applications in next-generation electronic devices. To realize new electronic devices with complex oxides, it is essential to understand the mechanisms of the electrical transport and to control the transport properties of complex oxide thin films.
In this talk, electrical transport phenomena and their electrical control will be discussed in nanoscale RNiO3 (R = rare-earth) thin films. The electrical transport in low-dimensional, strongly correlated LaNiO3 is explored in terms of band-width control by strain and dimensionality. A new concept of band-filling control in nanoscale NdNiO3 thin films by modulation (or remote) doping is discussed, and the remote doping from high-quality La-doped SrTiO3 into NdNiO3 thin films is experimentally studied. The remote doping approach allows for purely electronic modulation of a carrier density in the absence of other structural changes. Finally, the potentials and limitations of Modulation-doped Mott Field Effect Transistors (MM-FETs) for future “Mott” electronic devices are discussed.