Intrinsic Josephson junctions in the iron-based multi-band superconductor (V2Sr4O6)Fe2As2
Intrinsic Josephson junctions in the iron-based multi-band superconductor (V2Sr4O6)Fe2As2
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DOI：
10.1038/nphys3034
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发表时间：
2014-09-01
期刊：
影响因子：
19.6
通讯作者：
Batlogg, Bertram
中科院分区：
文献类型：
--
作者：
Moll, Philip J. W.;Zhu, Xiyu;Batlogg, Bertram
在层状超导体中，由于层间耦合足够低，约瑟夫森结可能在单元胞（1-3）内形成。这些本征约瑟夫森结（iJJ）系统(4)因其在量子计算中的应用潜力以及有效的太赫兹辐射源而引起了相当大的兴趣，从而关闭了著名的“太赫兹间隙”(5)。到目前为止，iJJ已经在单波段，铜基高t -c超导体中得到了证明，主要是在Bi-Sr-Ca-Cu-O中（参考文献6-8）。在这里，我们报告了铁基超导体（V2Sr4O6）Fe2As2中iJJ行为的明确实验证据。本征结是通过增加排列良好的平面内磁场时的磁通流电压的周期性振荡来识别的(9)。这种周期性可以用Josephson涡旋晶格和晶体结构之间的通约性效应来解释，这是Josephson涡旋被限制在iJJ堆中的标志（10,11）。这一发现将pnictide (V2Sr4O6)Fe2As2添加到Josephson结应用感兴趣的铜基iJJ材料中。特别是，可以实现基于多波段约瑟夫森耦合的新型器件。
In layered superconductors, Josephson junctions may be formed within the unit cell(1-3) as a result of sufficiently low inter-layer coupling. These intrinsic Josephson junction (iJJ) systems(4) have attracted considerable interest for their application potential in quantum computing as well as efficient sources of THz radiation, closing the famous 'THz gap'(5). So far, iJJ have been demonstrated in single-band, copper-based high-T-c superconductors, mainly in Bi-Sr-Ca-Cu-O (refs 6-8). Here we report clear experimental evidence for iJJ behaviour in the iron-based superconductor (V2Sr4O6)Fe2As2. The intrinsic junctions are identified by periodic oscillations of the flux-flow voltage on increasing a well-aligned in-plane magnetic field(9). The periodicity is explained by commensurability effects between the Josephson vortex lattice and the crystal structure, which is a hallmark signature of Josephson vortices confined into iJJ stacks(10,11). This finding adds the pnictide (V2Sr4O6)Fe2As2 to the copper-based iJJ materials of interest for Josephson junction applications. In particular, novel devices based on multi-band Josephson coupling may be realized.