Epitaxially strained Na0.7CoO2 thin films on SrTiO3 buffer layer

J. Y. Son; Y. H. Shin; Hyungjun Kim

doi:10.1016/j.jcrysgro.2008.11.072

Epitaxially strained Na_0.7CoO₂ thin films on SrTiO₃ buffer layer

J. Y. Son, Y. H. Shin, Hyungjun Kim

Department of Electrical and Electronic Engineering

Research output: Contribution to journal › Article › peer-review

1 Citation (Scopus)

Abstract

We prepared Na_0.7CoO₂ thin films on (0 0 1) Al₂O₃ substrates that showed a negligibly strained structure and a metallic behavior similar to Na_0.7CoO₂ single crystal. In particular, a Na_0.7CoO₂ thin film on a (1 1 1) SrTiO₃/(0 0 1) Al₂O₃ substrate exhibited an elongated c-lattice constant as well as an anomaly in the electric transporting behavior: a transition from an insulating state to a metallic state at 105 K. This change is caused by the structural symmetry break near the cubic-to-tetragonal transition temperature of SrTiO₃. From spectroscopic ellipsometry analysis, we obtained optical conductivities for the Na_0.7CoO₂ thin films on the Al₂O₃ and SrTiO₃/Al₂O₃ substrates. The Na_0.7CoO₂ thin film on the SrTiO₃/Al₂O₃ substrate exhibited higher energy splitting between e_g and a_1g than the Na_0.7CoO₂ thin film on the Al₂O₃ substrate, resulting from the c-lattice elongation.

Original language	English
Pages (from-to)	1021-1024
Number of pages	4
Journal	Journal of Crystal Growth
Volume	311
Issue number	4
DOIs	https://doi.org/10.1016/j.jcrysgro.2008.11.072
Publication status	Published - 2009 Feb 1

Bibliographical note

Funding Information:
This work was supported by the Brain Korea 21 Project 2006.

All Science Journal Classification (ASJC) codes

Condensed Matter Physics
Inorganic Chemistry
Materials Chemistry

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10.1016/j.jcrysgro.2008.11.072

Cite this

@article{cb34643cfbcb42c59fa9e7e331886a62,

title = "Epitaxially strained Na0.7CoO2 thin films on SrTiO3 buffer layer",

abstract = "We prepared Na0.7CoO2 thin films on (0 0 1) Al2O3 substrates that showed a negligibly strained structure and a metallic behavior similar to Na0.7CoO2 single crystal. In particular, a Na0.7CoO2 thin film on a (1 1 1) SrTiO3/(0 0 1) Al2O3 substrate exhibited an elongated c-lattice constant as well as an anomaly in the electric transporting behavior: a transition from an insulating state to a metallic state at 105 K. This change is caused by the structural symmetry break near the cubic-to-tetragonal transition temperature of SrTiO3. From spectroscopic ellipsometry analysis, we obtained optical conductivities for the Na0.7CoO2 thin films on the Al2O3 and SrTiO3/Al2O3 substrates. The Na0.7CoO2 thin film on the SrTiO3/Al2O3 substrate exhibited higher energy splitting between eg and a1g than the Na0.7CoO2 thin film on the Al2O3 substrate, resulting from the c-lattice elongation.",

author = "Son, {J. Y.} and Shin, {Y. H.} and Hyungjun Kim",

note = "Funding Information: This work was supported by the Brain Korea 21 Project 2006.",

year = "2009",

month = feb,

day = "1",

doi = "10.1016/j.jcrysgro.2008.11.072",

language = "English",

volume = "311",

pages = "1021--1024",

journal = "Journal of Crystal Growth",

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T1 - Epitaxially strained Na0.7CoO2 thin films on SrTiO3 buffer layer

AU - Son, J. Y.

AU - Shin, Y. H.

AU - Kim, Hyungjun

N1 - Funding Information: This work was supported by the Brain Korea 21 Project 2006.

PY - 2009/2/1

Y1 - 2009/2/1

N2 - We prepared Na0.7CoO2 thin films on (0 0 1) Al2O3 substrates that showed a negligibly strained structure and a metallic behavior similar to Na0.7CoO2 single crystal. In particular, a Na0.7CoO2 thin film on a (1 1 1) SrTiO3/(0 0 1) Al2O3 substrate exhibited an elongated c-lattice constant as well as an anomaly in the electric transporting behavior: a transition from an insulating state to a metallic state at 105 K. This change is caused by the structural symmetry break near the cubic-to-tetragonal transition temperature of SrTiO3. From spectroscopic ellipsometry analysis, we obtained optical conductivities for the Na0.7CoO2 thin films on the Al2O3 and SrTiO3/Al2O3 substrates. The Na0.7CoO2 thin film on the SrTiO3/Al2O3 substrate exhibited higher energy splitting between eg and a1g than the Na0.7CoO2 thin film on the Al2O3 substrate, resulting from the c-lattice elongation.

AB - We prepared Na0.7CoO2 thin films on (0 0 1) Al2O3 substrates that showed a negligibly strained structure and a metallic behavior similar to Na0.7CoO2 single crystal. In particular, a Na0.7CoO2 thin film on a (1 1 1) SrTiO3/(0 0 1) Al2O3 substrate exhibited an elongated c-lattice constant as well as an anomaly in the electric transporting behavior: a transition from an insulating state to a metallic state at 105 K. This change is caused by the structural symmetry break near the cubic-to-tetragonal transition temperature of SrTiO3. From spectroscopic ellipsometry analysis, we obtained optical conductivities for the Na0.7CoO2 thin films on the Al2O3 and SrTiO3/Al2O3 substrates. The Na0.7CoO2 thin film on the SrTiO3/Al2O3 substrate exhibited higher energy splitting between eg and a1g than the Na0.7CoO2 thin film on the Al2O3 substrate, resulting from the c-lattice elongation.

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