2022/07/26 by Shyam Sundar Yadav, Yadav, Shyam Sundar, Shelender Kumar +3
Materials Science · Physics and Astronomy · Engineering · #Electronic and Structural Properties of Oxides #Quantum and electron transport phenomena #Semiconductor materials and devices
paper · pdf · doi:10.48550/arxiv.2207.12933
Quasi-two-dimensional electron systems (q-2DES) are formed in various hetero-structures, including oxide interfaces. Oxygen vacancies (OVs) in oxides like SrTiO3 are known to produce electronic carriers. A novel way to produce \mathrmSrTiO3-δ on the surface using a low-energy H2 plasma is shown here. It results in a q-2DES with mobility as high as μ∼ 20,000 cm2V-1s-1, displaying quantum oscillations in magneto-resistance. We can achieve a sharper or weaker confinement potential by adjusting the process pressure. The system with sharper confinement displays clearer quantum oscillations and Kondo-like temperature dependence of resistance. OVs close to the surface behaving like a correlated Anderson impurity is responsible for the Kondo behaviour. Quantum oscillations are less prominent in the weakly confined system. A cross-over from weak-localization to anti-localization with temperature is seen, but no Kondo behavior. The process also results in a transparent conductor amenable to lithographic patterning. This conductor's standard figure of merit is comparable to poly-crystalline ITO films in the visible regime and extends with similar performance into the λ ∼ 1.5 μm telecommunication wavelength.