Scanning tunneling spectroscopy and break junction spectroscopy on iron-oxypnictide superconductor NdFeAs(O0.9F0.1)

A. Sugimoto, T. Ekino, R. Ukita, K. Shohara, H. Okabe, Jun Akimitsu, A. M. Gabovich

Research output: Contribution to journalArticle

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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 = 4Δ/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)/k BTc is about 3-4, kB being the Boltzmann constant. This value is consistent with the conventional weak-coupling s-wave Bardeen-Cooper-Schrieffer theory.

Original languageEnglish
Pages (from-to)1070-1072
Number of pages3
JournalPhysica C: Superconductivity and its Applications
Volume470
Issue number20
DOIs
Publication statusPublished - Nov 1 2010
Externally publishedYes

Fingerprint

Superconducting materials
Energy gap
Iron
Spectroscopy
Scanning
iron
scanning
Fluorine
Scanning tunneling microscopy
Topography
spectroscopy
Tunnels
Atoms
BCS theory
space transportation system
Electric potential
fluorine
tunnels
scanning tunneling microscopy
topography

Keywords

  • Iron-pnictide superconductor
  • STM
  • Tunneling spectroscopy

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Energy Engineering and Power Technology
  • Electronic, Optical and Magnetic Materials

Cite this

Scanning tunneling spectroscopy and break junction spectroscopy on iron-oxypnictide superconductor NdFeAs(O0.9F0.1). / Sugimoto, A.; Ekino, T.; Ukita, R.; Shohara, K.; Okabe, H.; Akimitsu, Jun; Gabovich, A. M.

In: Physica C: Superconductivity and its Applications, Vol. 470, No. 20, 01.11.2010, p. 1070-1072.

Research output: Contribution to journalArticle

Sugimoto, A. ; Ekino, T. ; Ukita, R. ; Shohara, K. ; Okabe, H. ; Akimitsu, Jun ; Gabovich, A. M. / Scanning tunneling spectroscopy and break junction spectroscopy on iron-oxypnictide superconductor NdFeAs(O0.9F0.1). In: Physica C: Superconductivity and its Applications. 2010 ; Vol. 470, No. 20. pp. 1070-1072.
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