Fabrication and Electrical Characterization of Correlated Oxide Field Effect Switching Devices for High Speed Electronics

  • Magazine Article
  • TBMG-36606
Published April 01, 2020 by Tech Briefs Media Group in United States
Language:
  • English

Metal insulator transitions (MITs) in oxides are an intriguing problem from both a fundamental materials physics and an applied technology perspective. Though the precise roles of electron correlations and lattice distortions on the phase transition remains an active area of research, many recent theoretical studies have suggested intimate interplay among the orbital splitting/polarization, correlation effects, and Peierls dimerization in the 3d1 system. Occupied states have been probed by x ray photoelectron spectroscopy (XPS), and a rough structure of unoccupied 3d-like states have been deduced by O K-edge x-ray absorption measurements. NbO2, a 4d1 system, like VO2 crystallizes in a distorted rutile type structure with Nb dimers and undergoes a temperature induced MIT, albeit at a considerably higher temperature of ~1083 K. It is commonly accepted that because 4d orbital valence states are more dispersed in both space and energy, Mott physics is less important in 4d transition metal oxides than in 3d ones. Along this line of reasoning, it is perhaps surprising that the insulating state of NbO2 persists to higher temperatures than that of VO2.