High-field superconducting phase diagrams including Fulde-Ferrell-Larkin-Ovchinnikov vortex states
High-field superconducting phase diagrams including Fulde-Ferrell-Larkin-Ovchinnikov vortex states
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DOI：
10.1103/physrevb.76.134504
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发表时间：
2007-06
影响因子：
3.7
通讯作者：
R. Ikeda
中科院分区：
文献类型：
--
作者：
R. Ikeda
基于在垂直于超导平面$(\mathbf{H}\ensuremath{\Vert}c)$的场中观察到的重费米子材料$\ mathm {Ce}\ mathm {Co}{\ mathm {in}}_{5}$的富尔德-费雷尔-拉金-奥夫奇尼可夫（FFLO）涡旋态，系统地研究了单轴各向异性超导体的包含FFLO态的超导相图。在无准粒子弛豫的弹道极限下，$\mathbf{H}\ensuremath{\Vert}c$和低温极限下的高场超导态不应该是沿$\mathbf{H}$调制的FFLO态，出现在$\ mathm {Ce}\ mathm {Co}{\ mathm {In}}_{5}$中，而是一种垂直于场调制的不同涡旋态。本文认为，QP弛豫率在${H}_{c2}(0)$附近的增强，可能源于非超导量子临界涨落，是后一种调制状态的缺失和奇怪的$\mathbf{H}\ensuremath{\Vert}c$相图的起源，其中FFLO状态明显不同于$\mathbf{H}\ensuremath{\perp}c$。
Motivated by a striking observation of a Fulde-Ferell-Larkin-Ovchinnikov (FFLO) vortex state in the heavy fermion material $\mathrm{Ce}\mathrm{Co}{\mathrm{In}}_{5}$ in fields perpendicular to the superconducting planes $(\mathbf{H}\ensuremath{\Vert}c)$, superconducting phase diagrams including an FFLO state of uniaxially anisotropic superconductors are systematically studied. In the ballistic limit with no quasiparticle (QP) relaxation, the high-field superconducting state in $\mathbf{H}\ensuremath{\Vert}c$ and in the low temperature limit should be not the FFLO state modulating along $\mathbf{H}$, appearing in $\mathrm{Ce}\mathrm{Co}{\mathrm{In}}_{5}$, but a different vortex state with a modulation perpendicular to the field. It is argued that an enhancement near ${H}_{c2}(0)$ of the QP relaxation rate, presumably originating from a nonsuperconducting quantum critical fluctuation, in this material is the origin of the absence of the latter modulated state and of the strange $\mathbf{H}\ensuremath{\Vert}c$ phase diagram in which the FFLO state is apparently different from that in $\mathbf{H}\ensuremath{\perp}c$.