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Title: The Vacancy-Induced Electronic Structure of the SrTiO 3-δ Surface

The emergence of a 2D electron gas (2DEG) on the (001) surface of oxygen-deficient strontium titanate (SrTiO 3-δ) is investigated. Using in situ soft X-ray spectroscopy and effective mass modeling, a series of quantitative band diagrams are developed to describe the evolution of near-surface and bulk carrier concentrations, downward band bending, and Fermi level along a lateral gradient of oxygen vacancies formed on SrTiO 3-δ by direct-current resistive heating under ultrahigh vacuum conditions. Electrons are accumulated over a 3 nm region near the surface, confined within a potential well with saturated 300 meV downward band bending. The relation between Fermi levels and carrier concentrations near the surface suggests the density of states near the surface is much lower than the bulk density of states, which is consistent with the quantum-confined subbands of a 2DEG. The quantitative relationship between the surface and bulk electronic structures developed in this work provides a guide for precise engineering of the oxygen-vacancy-induced 2DEG in SrTiO 3.
Authors:
ORCiD logo [1] ;  [2] ;  [3] ;  [2] ;  [2] ;  [2] ; ORCiD logo [3]
  1. Argonne National Lab. (ANL), Argonne, IL (United States); Northwestern Univ., Evanston, IL (United States)
  2. Northwestern Univ., Evanston, IL (United States)
  3. Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357; FG02-03ER15457; FG02-01ER45945
Type:
Accepted Manuscript
Journal Name:
Advanced Electronic Materials
Additional Journal Information:
Journal Volume: 5; Journal Issue: 1; Journal ID: ISSN 2199-160X
Publisher:
Wiley
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
National Science Foundation (NSF); Institute for Catalysis in Energy Processes (ICEP); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; SrTiO3 surface; effective mass modeling; electronic structure; in-situ x-ray spectroscopy; oxygen vacancies
OSTI Identifier:
1499278
Alternate Identifier(s):
OSTI ID: 1482131

Cook, Seyoung, Dylla, Maxwell T., Rosenberg, Richard A., Mansley, Zachary R., Snyder, G. Jeffrey, Marks, Laurence D., and Fong, Dillon D.. The Vacancy-Induced Electronic Structure of the SrTiO3-δ Surface. United States: N. p., Web. doi:10.1002/aelm.201800460.
Cook, Seyoung, Dylla, Maxwell T., Rosenberg, Richard A., Mansley, Zachary R., Snyder, G. Jeffrey, Marks, Laurence D., & Fong, Dillon D.. The Vacancy-Induced Electronic Structure of the SrTiO3-δ Surface. United States. doi:10.1002/aelm.201800460.
Cook, Seyoung, Dylla, Maxwell T., Rosenberg, Richard A., Mansley, Zachary R., Snyder, G. Jeffrey, Marks, Laurence D., and Fong, Dillon D.. 2018. "The Vacancy-Induced Electronic Structure of the SrTiO3-δ Surface". United States. doi:10.1002/aelm.201800460.
@article{osti_1499278,
title = {The Vacancy-Induced Electronic Structure of the SrTiO3-δ Surface},
author = {Cook, Seyoung and Dylla, Maxwell T. and Rosenberg, Richard A. and Mansley, Zachary R. and Snyder, G. Jeffrey and Marks, Laurence D. and Fong, Dillon D.},
abstractNote = {The emergence of a 2D electron gas (2DEG) on the (001) surface of oxygen-deficient strontium titanate (SrTiO3-δ) is investigated. Using in situ soft X-ray spectroscopy and effective mass modeling, a series of quantitative band diagrams are developed to describe the evolution of near-surface and bulk carrier concentrations, downward band bending, and Fermi level along a lateral gradient of oxygen vacancies formed on SrTiO3-δ by direct-current resistive heating under ultrahigh vacuum conditions. Electrons are accumulated over a 3 nm region near the surface, confined within a potential well with saturated 300 meV downward band bending. The relation between Fermi levels and carrier concentrations near the surface suggests the density of states near the surface is much lower than the bulk density of states, which is consistent with the quantum-confined subbands of a 2DEG. The quantitative relationship between the surface and bulk electronic structures developed in this work provides a guide for precise engineering of the oxygen-vacancy-induced 2DEG in SrTiO3.},
doi = {10.1002/aelm.201800460},
journal = {Advanced Electronic Materials},
number = 1,
volume = 5,
place = {United States},
year = {2018},
month = {11}
}

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