Field dependence of the vortex core size probed by scanning tunneling microscopy
- Autonomous Univ. of Madrid (Spain). Inst. of Materials Science Nicolas Cabrera Condensed Matter Physics and Center (IFIMAC), Low Temperature Lab.; Autonomous Univ. of Madrid (Spain). Associated Unit of Low Temperature and High fields Magneticos
- Autonomous Univ. of Madrid (Spain). Inst. of Materials Science Nicolas Cabrera Condensed Matter Physics and Center (IFIMAC), Low Temperature Lab.; Autonomous Univ. of Madrid (Spain). Associated Unit of Low Temperature and High fields Magneticos
- Univ. of Valenci, Paterna (Spain). Inst. of Molecular Science (ICMol)
- Ames Lab., Ames, IA (United States)
We study the spatial distribution of the density of states (DOS) at zero bias N(r) in the mixed state of single and multigap superconductors. We provide an analytic expression for N(r) based on deGennes' relationship between DOS and the order parameter that reproduces well scanning tunneling microscopy (STM) data in several superconducting materials. In the single gap superconductor β-Bi2 Pd, we find that N(r) is governed by a length scale ξH = $$\sqrt{Φ0/2πH}$$ which decreases in rising fields. The vortex core size $$C$$ ∝ (d Δ/dr|r→0)₋1 differs from ξH by a material dependent numerical factor. The new data on the tunneling conductance and vortex lattice of the 2H-NbSe1.8S0.2 show the in-plane isotropic vortices, suggesting that substitutional scattering removes the in-plane anisotropy found in the two-gap superconductor 2H-NbSe2. We fit the tunneling conductance of 2H-NbSe1.8S0.2 to a two gap model and calculate the vortex core size $$C$$ for each band. We find that $$C$$ is field independent and has the same value for both bands. We also analyze the two-band superconductor 2H-NbSe2 and find the same result. Lastly, we conclude that, independently of the magnetic field induced variation of the order parameter values in both bands, the spatial variation of the order parameter close to the vortex core is the same for all bands.
- Research Organization:
- Ames Lab., Ames, IA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); Spanish Ministry of Economy and Competitiveness; European Union EU; COLCIENCIAS Programa Doctorados en el Exterior Convocatoria; European Research Council (ERC)
- Grant/Contract Number:
- AC02-07CH11358; FIS2014-54498-R; MAT2014-56143-R; 679080; MAT2014-52919-REDC; MDM2015-0538; MDM-2014-0377
- OSTI ID:
- 1326846
- Alternate ID(s):
- OSTI ID: 1275980
- Report Number(s):
- IS-J-9079; PRBMDO
- Journal Information:
- Physical Review B, Vol. 94, Issue 1; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Full-gap superconductivity in spin-polarised surface states of topological semimetal β-PdBi2
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journal | October 2017 |
Expansion of a superconducting vortex core into a diffusive metal
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journal | June 2018 |
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