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Title: Stoichiometry-driven metal-to-insulator transition in NdTiO{sub 3}/SrTiO{sub 3} heterostructures

By controlling stoichiometry via a hybrid molecular beam epitaxy approach, we report on the study of thin film growth and the electronic transport properties of phase-pure, epitaxial NdTiO{sub 3}/SrTiO{sub 3} heterostructures grown on (001) (La{sub 0.3}Sr{sub 0.7})(Al{sub 0.65}Ta{sub 0.35})O{sub 3} (LSAT) substrates as a function of cation stoichiometry in NdTiO{sub 3}. Despite the symmetry mismatch between bulk NdTiO{sub 3} and the substrate, NdTiO{sub 3} films grew in an atomic layer-by-layer fashion over a range of cation stoichiometry; however amorphous films resulted in cases of extreme cation non-stoichiometry. Temperature-dependent sheet resistance measurements were consistent with Fermi-liquid metallic behavior over a wide temperature range, but revealed a remarkable crossover from metal-to-insulator (M-I) type behavior at low temperatures for all compositions. A direct correlation between cation stoichiometry, transport behavior, and the temperature of M-I transition is established.
Authors:
; ; ; ;  [1]
  1. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 (United States)
Publication Date:
OSTI Identifier:
22293048
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CATIONS; CRYSTAL GROWTH; FERMI GAS; LIQUID METALS; MOLECULAR BEAM EPITAXY; STOICHIOMETRY; STRONTIUM TITANATES; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0065-0273 K; THIN FILMS