Strain effects on the electron effective mass in SrTiO$_3$

ORAL

Abstract

Strain can greatly affect the electronic properties of thin layers in epitaxial heterostructures, leading to improved transport properties. In SrTiO$_3$-based heterostructures, strain can lift the degeneracy and modify the order of the states near the conduction-band minimum. Using density functional theory with the screened hybrid functional of Heyd, Scuseria, and Ernzerhof (HSE) we study the effects of strain on the energetic ordering and effective mass of the lowest-energy conduction-band states in SrTiO$_3$3. We predict that biaxial stress in the (001) or (110) planes results in the lowest-energy conduction-band state having significantly smaller electron mass in the in-plane directions compared to unstrained SrTiO$_3$, thus suggesting that pseudomorphic growth is a promising route to increasing the electron mobility in epitaxial films. We propose possible substrates that may lead to SrTiO$_3$ films with enhanced electron mobilities, and report deformation potentials that allow accurate prediction of conduction-band splittings for arbitrary strain configurations.

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Authors

  • Anderson Janotti

    University of California, Santa Barbara, Materials Department, University of California Santa Barbara, Materials Department, University of California, Santa Barbara, Materials Department, University of California at Santa Barbara

  • Daniel Steiauf

    Materials Department, University of California Santa Barbara, Materials Department, University of California, Santa Barbara

  • C.G. Van de Walle

    Materials Department, University of California, Santa Barbara, Materials Department, University of California Santa Barbara, University of California, Santa Barbara, Materials Department, University of California Santa Barbara, CA 93106-5050, Materials Department, University of California at Santa Barbara, Materials Department, University of California, Santa Barbara, California, CA