Subband Structure of a Two-Dimensional Electron Gas Formed at the Polar Surface of the Strong Spin-Orbit Perovskite KTaO3

P. D. C. King, R. H. He, T. Eknapakul, P. Buaphet, S-K Mo, Y. Kaneko, S. Harashima, Y. Hikita, M. S. Bahramy, C. Bell, Z. Hussain, Y. Tokura, Z-X Shen, H. Y. Hwang, F. Baumberger*, W. Meevasana, Chris Bell

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

119 Citations (Scopus)

Abstract

We demonstrate the formation of a two-dimensional electron gas (2DEG) at the (100) surface of the 5d transition-metal oxide KTaO3. From angle-resolved photoemission, we find that quantum confinement lifts the orbital degeneracy of the bulk band structure and leads to a 2DEG composed of ladders of subband states of both light and heavy carriers. Despite the strong spin-orbit coupling, our measurements provide a direct upper bound for the potential Rashba spin splitting of only Delta k(parallel to) similar to 0.02 angstrom(-1) at the Fermi level. The polar nature of the KTaO3(100) surface appears to help mediate the formation of the 2DEG as compared to nonpolar SrTiO3(100).

Original languageEnglish
Article number117602
Number of pages5
JournalPhysical Review Letters
Volume108
Issue number11
DOIs
Publication statusPublished - 14 Mar 2012

Keywords

  • OXIDE HETEROSTRUCTURES
  • SUPERCONDUCTIVITY
  • INTERFACES
  • COEXISTENCE
  • PHYSICS
  • SRTIO3
  • STATE
  • PHASE

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