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ID 46729
file
creator
Ekino, T.
Ukita, R.
Shohara, K.
Okabe, H.
Akimitsu, J.
Gabovich, A.M.
subject
Iron-pnictide superconductor
STM
tunneling spectroscopy
NDC
Physics
abstract
Iron-oxypnictide superconductor NdFeAs(O0.9F0.1) was studied using both low-temperature scanning tunneling microscopy/spectroscopy (STM/STS) and tunnel break junction (BJ) methods. STM topography showed granular and spot structures with a typical size of several nanometers, most probably governed by fluorine atom distribution. The majority of STS conductance, G, versus voltage, V, curves revealed V-shaped structures, whereas some of G(V) dependences possessed coherent gap peaks or kinks at gap energies. At the same time, G(V) dependences obtained by the BJ technique showed clear-cut coherence peaks with peak-to-peak distances Vpp = 4 Δ/e ~ 25 mV at 4.2 K, where Δ is the superconducting energy gap, e > 0 is the elementary charge. This yields Δ (0) = 6~7 meV, so that the ratio 2Δ(0)/kBTc is about 3~4, kB being the Boltzmann constant. This value is consistent with the conventional weak-coupling s-wave Bardeen-Cooper-Schrieffer theory.
description
This research was supported by Grant-in-Aid for Scientific Research (No. 19540370) from JSPS, Japan. AMG highly appreciates the 2009 Visitors Program of the Max Planck Institute for the Physics of Complex Systems (Dresden, Germany).
journal title
Physica C: Superconductivity and its Applications
volume
Volume 470
issue
Issue 20
start page
1070
end page
1072
date of issued
2010-10-01
publisher
Elsevier B.V.
issn
0921-4534
ncid
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
author
rights
Copyright (c) 2010. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
This is not the published version. Please cite only the published version. この論文は出版社版でありません。引用の際には出版社版をご確認ご利用ください。
relation url
department
Graduate School of Integrated Arts and Sciences