Searching for Gap Zeros in Sr2RuO4 via Field-Angle-Dependent Specific-Heat Measurement

被引：54

作者：

Kittaka, Shunichiro ^{[1
]}

Nakamura, Shota ^{[1
,9
]}

Sakakibara, Toshiro ^{[1
]}

Kikugawa, Naoki ^{[2
]}

Terashima, Taichi ^{[2
]}

Uji, Shinya ^{[2
,3
]}

Sokolov, Dmitry A. ^{[4
]}

Mackenzie, Andrew P. ^{[4
]}

Irie, Koki ^{[5
]}

Tsutsumi, Yasumasa ^{[6
,7
]}

Suzuki, Katsuhiro ^{[8
]}

Machida, Kazushige ^{[5
]}

机构：

[1] Univ Tokyo, Inst Solid State Phys, Kashiwa, Chiba 2778581, Japan

[2] Natl Inst Mat Sci, Tsukuba, Ibaraki 3050003, Japan

[3] Univ Tsukuba, Grad Sch Pure & Appl Sci, Tsukuba, Ibaraki 3058577, Japan

[4] Max Planck Inst Chem Phys Solids, Nothnitzer Str 40, D-01187 Dresden, Germany

[5] Ritsumeikan Univ, Dept Phys, Kusatsu, Shiga 5258577, Japan

[6] Univ Tokyo, Dept Basic Sci, Meguro Ku, Tokyo 1538902, Japan

[7] RIKEN, Condensed Matter Theory Lab, Wako, Saitama 3510198, Japan

[8] Ritsumeikan Univ, Res Org Sci & Technol, Kusatsu, Shiga 5258577, Japan

[9] Nagoya Inst Technol, Grad Sch Engn, Dept Engn Phys Elect & Mech, Nagoya, Aichi 4668555, Japan

来源：

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN | 2018年 / 87卷 / 09期

关键词：

TRIPLET SUPERCONDUCTOR SR2RUO4; UNCONVENTIONAL SUPERCONDUCTORS; NODES; CONDUCTIVITY; ANISOTROPY; VORTEX; STATES; BANDS; NQR;

D O I：

10.7566/JPSJ.87.093703

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

The gap structure of Sr2RuO4, which is a longstanding candidate for a chiral p-wave superconductor, has been investigated from the perspective of the dependence of its specific heat on magnetic field angles at temperatures as low as 0.06 K (similar to 0.04T(c)). Except near H-c2, its fourfold specific-heat oscillation under an in-plane rotating magnetic field is unlikely to change its sign down to the lowest temperature of 0.06 K. This feature is qualitatively different from nodal quasiparticle excitations of a quasi-two-dimensional superconductor possessing vertical lines of gap minima. The overall specific-heat behavior of Sr2RuO4 can be explained by Doppler-shifted quasiparticles around horizontal line nodes on the Fermi surface, whose in-plane Fermi velocity is highly anisotropic, along with the occurrence of the Pauli-paramagnetic effect. These findings, in particular, the presence of horizontal line nodes in the gap, call for a reconsideration of the order parameter of Sr2RuO4.

引用

页码：0937031 / 0937035

页数：5

共 56 条

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