Tunable two-dimensional electron system at the (110) surface of SnO${}_2$

Abstract

We report the observation of a two-dimensional electron system (2DES) at the $(110)$ surface of the transparent bulk insulator SnO${}_2$, and the tunability of its carrier density by means of temperature or Eu deposition. The 2DES is insensitive to surface reconstructions and, surprisingly, it survives even after exposure to ambient conditions --an extraordinary fact recalling the well known catalytic properties SnO${}_2$. Our data show that surface oxygen vacancies are at the origin of such 2DES, providing key information about the long-debated origin of $n$-type conductivity in SnO${}_2$, at the basis of a wide range of applications. Furthermore, our study shows that the emergence of a 2DES in a given oxide depends on a delicate interplay between its crystal structure and the orbital character of its conduction band.

arXiv comment11 pages, 12 figures

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Cited by in corpus (2)

• Anisotropic Electronic Structure of the Two-Dimensional Electron Gas at the AlOx/KTaO3(110) interface
• A Laser-ARPES View of the 2D Electron Systems at LaAlO3/SrTiO3 and Al/SrTiO3 Interfaces