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Title: Scanning tunneling microscopy study of morphology and electronic properties in (K{sub 0.7}Na{sub 0.3})Fe{sub 2−y}Se{sub 2} single crystal

Abstract

We investigated the microstructure of the iron selenide superconductor (K{sub 0.7}Na{sub 0.3})Fe{sub 2−y}Se{sub 2} with a T{sub c} = 32 K and a near 100% Meissner screening volume fraction. Topography and electron transport properties were studied using electron microscopy and ultra-high vacuum scanning tunneling microscopy (STM) techniques. Room temperature STM measurements reliably identify spatial variations of the local electronic properties of this material. The studied crystals consist of continuous regions with significantly different shapes of current-voltage curves reflecting different electronic transport properties of these regions. Fitting of the local current-voltage curves with the Simmons model for metal-dielectric-metal structure confirmed a phase separation in the sample to a metal and semiconducting phases. The observed regions have dimensions in the range of several tenths of a micrometer and indicate a phase separation in the sample.

Authors:
;  [1];  [2];  [3];  [4]; ; ;  [5];  [6];  [3];  [2];  [2]
  1. Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 1(2), Leninskie Gory, GSP-1, Moscow 119991 (Russian Federation)
  2. (Russian Federation)
  3. Low Temperature Physics and Superconductivity Department, Physics Faculty, Lomonosov Moscow State University, 119991 Moscow (Russian Federation)
  4. Institute for Materials Research, Tohoku University, 980-8577 Sendai (Japan)
  5. Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow (Russian Federation)
  6. National Institute for Material Science, Tsukuba 305-0047 (Japan)
Publication Date:
OSTI Identifier:
22308539
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 4; 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; DIELECTRIC MATERIALS; ELECTRIC CONDUCTIVITY; ELECTRICAL PROPERTIES; ELECTRON MICROSCOPY; IRON COMPOUNDS; MICROSTRUCTURE; MONOCRYSTALS; POTASSIUM COMPOUNDS; SCANNING TUNNELING MICROSCOPY; SELENIUM COMPOUNDS; SODIUM COMPOUNDS; SUPERCONDUCTORS; TEMPERATURE RANGE 0013-0065 K; TEMPERATURE RANGE 0273-0400 K; TRANSITION TEMPERATURE

Citation Formats

Trifonov, A. S., E-mail: trifonov.artem@phys.msu.ru, Presnov, D. E., Low Temperature Physics and Superconductivity Department, Physics Faculty, Lomonosov Moscow State University, 119991 Moscow, Ovchenkov, Y. A., Belosludov, R., Boltalin, A. I., Liu, M., Morozov, I. V., Nejo, H., Vasiliev, A. N., Theoretical Physics and Applied Mathematics Department, Institute of Physics and Technology, Ural Federal University, Ekaterinburg 620002, and National University of Science and Technology 'MISiS', Moscow 119049. Scanning tunneling microscopy study of morphology and electronic properties in (K{sub 0.7}Na{sub 0.3})Fe{sub 2−y}Se{sub 2} single crystal. United States: N. p., 2014. Web. doi:10.1063/1.4891227.
Trifonov, A. S., E-mail: trifonov.artem@phys.msu.ru, Presnov, D. E., Low Temperature Physics and Superconductivity Department, Physics Faculty, Lomonosov Moscow State University, 119991 Moscow, Ovchenkov, Y. A., Belosludov, R., Boltalin, A. I., Liu, M., Morozov, I. V., Nejo, H., Vasiliev, A. N., Theoretical Physics and Applied Mathematics Department, Institute of Physics and Technology, Ural Federal University, Ekaterinburg 620002, & National University of Science and Technology 'MISiS', Moscow 119049. Scanning tunneling microscopy study of morphology and electronic properties in (K{sub 0.7}Na{sub 0.3})Fe{sub 2−y}Se{sub 2} single crystal. United States. doi:10.1063/1.4891227.
Trifonov, A. S., E-mail: trifonov.artem@phys.msu.ru, Presnov, D. E., Low Temperature Physics and Superconductivity Department, Physics Faculty, Lomonosov Moscow State University, 119991 Moscow, Ovchenkov, Y. A., Belosludov, R., Boltalin, A. I., Liu, M., Morozov, I. V., Nejo, H., Vasiliev, A. N., Theoretical Physics and Applied Mathematics Department, Institute of Physics and Technology, Ural Federal University, Ekaterinburg 620002, and National University of Science and Technology 'MISiS', Moscow 119049. Mon . "Scanning tunneling microscopy study of morphology and electronic properties in (K{sub 0.7}Na{sub 0.3})Fe{sub 2−y}Se{sub 2} single crystal". United States. doi:10.1063/1.4891227.
@article{osti_22308539,
title = {Scanning tunneling microscopy study of morphology and electronic properties in (K{sub 0.7}Na{sub 0.3})Fe{sub 2−y}Se{sub 2} single crystal},
author = {Trifonov, A. S., E-mail: trifonov.artem@phys.msu.ru and Presnov, D. E. and Low Temperature Physics and Superconductivity Department, Physics Faculty, Lomonosov Moscow State University, 119991 Moscow and Ovchenkov, Y. A. and Belosludov, R. and Boltalin, A. I. and Liu, M. and Morozov, I. V. and Nejo, H. and Vasiliev, A. N. and Theoretical Physics and Applied Mathematics Department, Institute of Physics and Technology, Ural Federal University, Ekaterinburg 620002 and National University of Science and Technology 'MISiS', Moscow 119049},
abstractNote = {We investigated the microstructure of the iron selenide superconductor (K{sub 0.7}Na{sub 0.3})Fe{sub 2−y}Se{sub 2} with a T{sub c} = 32 K and a near 100% Meissner screening volume fraction. Topography and electron transport properties were studied using electron microscopy and ultra-high vacuum scanning tunneling microscopy (STM) techniques. Room temperature STM measurements reliably identify spatial variations of the local electronic properties of this material. The studied crystals consist of continuous regions with significantly different shapes of current-voltage curves reflecting different electronic transport properties of these regions. Fitting of the local current-voltage curves with the Simmons model for metal-dielectric-metal structure confirmed a phase separation in the sample to a metal and semiconducting phases. The observed regions have dimensions in the range of several tenths of a micrometer and indicate a phase separation in the sample.},
doi = {10.1063/1.4891227},
journal = {Journal of Applied Physics},
number = 4,
volume = 116,
place = {United States},
year = {Mon Jul 28 00:00:00 EDT 2014},
month = {Mon Jul 28 00:00:00 EDT 2014}
}