Defects and transport in oxide heterostructures*

Complex oxide heterostructures have been intensively investigated in recent years. However, the widely used transition-metal oxides suffer from low carrier mobility, which limits device applications. For applications in electronics, attention has shifted to materials such as BaSnO₃ and Ga₂O₃. They have large band gaps, rendering them suitable for transparent conductors and for high-frequency and power electronics, but can be highly n-type doped and exhibit good transport properties. Better control of dopants and point defects is still needed in order to improve materials quality and enable further applications. I will show how cutting-edge first-principles modeling, using advanced hybrid functional calculations within density functional theory, can shed light on the multiple aspects of this problem: band alignment and confinement of two-dimensional electron gases [1,2,3,4], carrier scattering and mobility [5,6], doping [7,8], point defects and their impact on carrier concentrations [8], energetics and electronic structure of alloys [3,4], and optical properties [9,10].

I gratefully acknowledge collaborations with L. Bjaalie, L. Gordon, B. Himmetoglu, A. Janotti, Y. Kang, S. KC, K. Krishnaswamy, J. L. Lyons, H. Peelaers, J. B. Varley, and L. Weston.

[1] L. Bjaalie et al., New J. Phys. 16, 025005 (2014).
[2] K. Krishnaswamy et al., Appl. Phys. Lett. 108, 083501 (2016).
[3] H. Peelaers et al., Phys. Rev. B 92, 085206 (2015).
[4] H. Peelaers et al., Appl. Phys. Lett. 112, 242101 (2018).
[5] K. Krishnaswamy et al., Phys. Rev. B 95, 205202 (2017).
[6] Y. Kang et al., J. Phys.: Condens. Matter 29, 234001 (2017).
[7] H. Peelaers and C. G. Van de Walle, Phys. Rev. B 94, 195203 (2016).
[8] L. Weston et al., Phys. Rev. B 97, 054112 (2018).
[9] H. Peelaers and C. G. Van de Walle, Appl. Phys. Lett. 111, 182104 (2017).
[10] Y. Kang et al., Appl. Phys. Lett. 112, 062106 (2018).