Localization and interaction effects in ultrathin epitaxial NbN superconducting films

被引：23

作者：

Ezaki, S. ^{[1
]}

Makise, K. ^{[2
]}

Shinozaki, B. ^{[1
]}

Odo, T. ^{[1
]}

Asano, T. ^{[1
]}

Terai, H. ^{[2
]}

Yamashita, T. ^{[2
]}

Miki, S. ^{[2
]}

Wang, Z. ^{[2
]}

机构：

[1] Kyushu Univ, Dept Phys, Fukuoka 8108560, Japan

[2] Natl Inst Informat & Commun Technol, Kobe, Hyogo 6512492, Japan

来源：

JOURNAL OF PHYSICS-CONDENSED MATTER | 2012年 / 24卷 / 47期

关键词：

INSULATOR TRANSITION; TEMPERATURE; RESISTANCE; DETECTOR;

D O I：

10.1088/0953-8984/24/47/475702

中图分类号：

O469 [凝聚态物理学];

学科分类号：

070205 ;

摘要：

For epitaxial NbN films with thickness d, 2.0 nm <= d <= 20.5 nm, we observed a sharp superconducting transition, for which the transition temperature T-c monotonically decreased with increasing 1/d. Regarding the suppression of T-c, the sheet resistance R-sq dependence of T-c closely fitted the Finkel'stein formula from localization theory, with a reasonable value of the electron mean free path comparable to atomic distance, which was used as a fitting parameter. On the other hand, the critical sheet resistance R-c, at which the superconducting-insulator transition was expected, was approximately one-third of the universal value R-q =h/4e(2) suggested by the dirty boson model for self-duality. It is concluded that T-c depression in the present NbN system is determined by localization theory but not the dirty boson model.

引用

页数：5

共 26 条

[1] ENHANCEMENT OF SUPERCONDUCTIVITY AND OBSERVATION OF ANTILOCALIZATION IN THIN METAL-FILMS BY SUPPRESSION OF ELECTRON-INTERACTION EFFECTS [J].