Pseudogap in a thin film of a conventional superconductor.
A superconducting state is characterized by the gap in the electronic density of states, which vanishes at the superconducting transition temperature T(c). It was discovered that in high-temperature superconductors, a noticeable depression in the density of states, the pseudogap, still remains even at temperatures above T(c). Here, we show that a pseudogap exists in a conventional superconductor, ultrathin titanium nitride films, over a wide range of temperatures above T(c). Our study reveals that this pseudogap state is induced by superconducting fluctuations and favoured by two-dimensionality and by the proximity to the transition to the insulating state. A general character of the observed phenomenon provides a powerful tool to discriminate between fluctuations as the origin of the pseudogap state and other contributions in the layered high-temperature superconductor compounds.
SPSMS, UMR-E 9001, CEA-INAC/UJF-Grenoble 1, 17 rue des martyrs, 38054 Grenoble cedex 9, France. benjamin.sacepe@grenoble.cnrs.fr
Benjamin
B
Sacépé
Claude
C
Chapelier
Tatyana I
TI
Baturina
Valerii M
VM
Vinokur
Mikhail R
MR
Baklanov
Marc
M
Sanquer
Nature. 2000 Aug 3;406(6795):486-8
10952303
Phys Rev Lett. 2007 Dec 21;99(25):257003
18233550
Phys Rev B Condens Matter. 1991 Aug 1;44(5):2418-2421
9999808
Phys Rev Lett. 1996 Aug 26;77(9):1837-1840
10063184
Phys Rev Lett. 2006 Mar 17;96(10):107003
16605778
Phys Rev Lett. 2007 Mar 23;98(12):127003
17501151
Phys Rev Lett. 2008 Oct 10;101(15):157006
18999631
Phys Rev Lett. 2001 Jul 2;87(1):017001
11461485
Science. 1987 Mar 6;235(4793):1196-8
17818979
Science. 2006 Dec 22;314(5807):1888-9
17185592
Phys Rev Lett. 2004 Nov 19;93(21):217005
15601055