Gor'kov's expansion and the dHvA effect in the vortex state

Citation
T. Maniv et al., Gor'kov's expansion and the dHvA effect in the vortex state, J PHYS CH S, 59(10-12), 1998, pp. 1841-1845
Citations number
15
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
ISSN journal
00223697 → ACNP
Volume
59
Issue
10-12
Year of publication
1998
Pages
1841 - 1845
Database
ISI
SICI code
0022-3697(199810/12)59:10-12<1841:GEATDE>2.0.ZU;2-
Abstract
The validity of Gor'kov's expansion in the small superconducting order para meter near the upper critical field H-c2 of type II superconductors at low temperatures is examined in the light of the accumulated experimental data of the dHvA effect in the vortex state. Using a 2D electron gas model, it i s shown that a small amount of thermal smearing is sufficient to ensure the validity of the expansion within a significantly broad field range below H -c2. The lowest order (i.e. quadratic) term in this expansion is insensitiv e to the inhomogeneity of the pair potential in the vortex state and tends to cancel the zeroth order (i.e. normal electrons) term. Higher order terms are found, in the asymptotic limit, root E-F/(h) over bar omega(c) >> 1, t o be much smaller than the corresponding terms in the random vortex lattice model, thus reflecting weak 'scattering' of quasi-particles by the vortex lattice. This picture seems to account qualitatively for a common feature o bserved in almost all experiments so far, namely the crossover of the Dingl e plot from a relatively large slope just below H-c2 to a smaller slope at lower fields. (C) 1998 Elsevier Science Ltd. All rights reserved.