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Formation and Tuning of 2D Electron Gas in Perovskite Heterostructures
Author(s) -
Maznichenko Igor V.,
Ostanin Sergey,
Ernst Arthur,
Henk Juergen,
Mertig Ingrid
Publication year - 2020
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201900540
Subject(s) - fermi gas , heterojunction , superlattice , condensed matter physics , polar , materials science , context (archaeology) , ionic bonding , perovskite (structure) , electron , epitaxy , chemical physics , layer (electronics) , chemistry , nanotechnology , physics , ion , crystallography , paleontology , organic chemistry , quantum mechanics , astronomy , biology
Oxide interfaces provide very intriguing phenomena, in particular a 2D electron gas (2DEG) emerging between robustly insulating perovskites. The 2DEG was detected in 2004 beneath polar LaAlO 3 (LAO) epitaxially grown on TiO 2 ‐terminated SrTiO 3 (001) (STO). Herein, recent first‐principles studies of 2DEGs are reviewed. Using a Green function method, the family of the polar/nonpolar (001) interfaces: LAO/STO, LaFeO 3 /STO, and STO/KTaO 3 is computed. In the context of 2DEG, one of two insulating perovskites, at least, must be polar. The effect of a polar/polar interface is modeled for LAO/KTaO 3 (001) and also for the (110) and (111) interfaces of LAO/STO. Starting from the defectless superlattice with its two differently terminated interfaces, we demonstrate that the 2DEG and 2D hole gas appear there, respectively, due to the presence of excessive electrons or holes. 2DEG is evaluated by its layer‐resolved density profile along [001], as well as the Fermi surface cross sections and effective masses, which are directly related to the transport properties. The effects of intermixed cations, their vacancies, and oxygen vacancies at each interface of LAO/STO are calculated. Finally, we show how to tune reversibly the 2DEG by changing the electronic balance at the LAO surface that mimics the effect of ionic liquid gating.