We present an experimental and analytical study of resonances in the current-voltage characteristics of single and double row triangular Josephson arrays. The magnetic field dependences of the voltage positions of the resonances have been measured for various cell inductances and junction critical currents. In double row arrays, we have observed a peculiar resonance, whose voltage position decreases with magnetic field. We derive the spectrum of linear electromagnetic waves propagating in the arrays. In the double row array, the spectrum consists of many branches that differ by the behavior of the Josephson junctions transverse to the bias current direction. The measured magnetic field dependence of the resonance voltages is mapped to the linear mode spectrum and good agreement between experiments and model is found.
Collective Josephson vortex dynamics in a finite number of intrinsic Josephson junctions
本文报道了在Bi $_{2}$ Sr $_{2}$ CaCu $_{2}$ O $_{8+x}$单晶中由本征约瑟夫森结叠层中的约瑟夫森涡旋晶格激发的集体横向等离子体模的实验证实。通过分析系统的电流-电压特性的约瑟夫森涡流区域中的多个子分支的温度($T$)和磁场($H$)依赖性来确认激发。在近静态的约瑟夫森涡旋状态下,一个低的隧道偏置电流,观察到明显的磁阻振荡,这代表了沿c轴的三角晶格涡旋配置。在足够高的磁场和高偏置电流的动态涡旋状态下,观察到单个约瑟夫森涡旋流分支分裂成多个子分支。对不同$H$场的子分支的详细研究表明,子分支代表约瑟夫森涡旋晶格沿c轴的不同模式,具有从三角形到矩形晶格的不同构型。这些多个子分支合并到一个单一的曲线在一个特征温度,以上的约瑟夫森涡晶格的动力学结构转变是预期。
Josephson lattice structure in mesoscopic intrinsic Josephson junctions by means of flux-flow resistance in Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$
本文研究了磁场取向非常接近于$ab$面的c轴电流作用下Bi $_2$ Sr $_2$ CaCu $_2$ O $_{8+δ}$(Bi 2212)中约瑟夫森涡旋(JV)系统的动力学性质.作为磁场的函数,c轴JV通量流动阻力根据所提出的JV三角形结构周期性地振荡。我们观察到,这个振荡周期在一定的电场以上变为两倍,表明结构从三角形转变为正方形结构。在垂直于外场方向宽度较小的结中,这种过渡场变得较低。我们认为这种现象是由于Koshelev所指出的本征约瑟夫森结的表面电流引起的JV晶格边缘变形的影响。
Periodic Oscillations of Josephson-Vortex Flow Resistance in Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+y}$
为了研究本征约瑟夫森结中的约瑟夫森涡旋系统,我们测量了Bi ${}_2$ Sr ${}_2$ CaCu ${}_2$ O ${}_{8+y}$单晶中流动阻力随平行于$ab$面的磁场的变化。虽然它是已知的流动阻力增加顺利增加,增加领域,我们发现了新的振荡的涡流阻力在小电流制度。振荡的周期对应于为每个“{\it two}”约瑟夫森结添加“{\it one}”涡旋量子所需的场。沿$ab$平面的Josephson涡旋的晶格间距与结的尺寸之间的公度性与涡旋的流速有关。结果表明,在振荡状态下,约瑟夫森涡旋形成三角形格子。
Scaling behavior of the crossover to short-stack regimes of Josephson vortex lattices in Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ stacks
本文系统地研究了具有不同几何形状和超导各向异性参数的Bi $_2$ Sr $_2$ CaCu $_2$ O $_{8+δ}$微制造结中约瑟夫森涡旋(JV)流阻的振荡。当平行于$ab$平面的外加磁场增加时,具有对应于$ϕ_0/2$ par原子约瑟夫森结的周期的振荡变为具有双倍周期的振荡。该交叉由结长度和各向异性参数两者缩放,表明有利于三角形JV晶格的体电感耦合被替换为JV晶格的占主导地位的相互作用的表面变形能。这些结果表明,在较小且各向异性更强的样品中,在较高的磁场下,同相正方形JV晶格明显。
Exact solution of the Lawrence-Doniach model in parallel magnetic fields
首次得到了层状超导体在平行磁场中Lawrence-Doniach模型的完整精确解析解。通过解决一个非平凡的数学问题的自由能泛函的精确最小化,我们得到一个封闭的,自洽系统的平均场方程只涉及两个变量。这些方程的精确解证明了约瑟夫森涡旋同时渗透到所有的障碍,产生一个全新的表达较低的临界场,驳斥了三角形约瑟夫森涡旋晶格的概念,并澄清了物理的夫琅和费振荡的总临界约瑟夫森电流。PACS编号:74.80.Dm、74.20.De、74.50.+ R
Quantum Interference in Superconducting Wire Networks and Josephson Junction Arrays: Analytical Approach based on Multiple-Loop Aharonov-Bohm Feynman Path-Integrals
Materials with transition metals in triangular lattices are of great interest for their potential combination of strong correlation, exotic magnetism and electronic topology. Kagome nets are of particular importance since the discovery of geometrically frustrated magnetism and topological band structures in crystals like Herbertsmithite and Fe3Sn2, respectively. KV3Sb5 was discovered to be a layered topological metal with a Kagome net of vanadium. Here, we fabricated Josephson Junctions (JJ) of K1-xV3Sb5 and induced superconductivity over long junction lengths. Through magnetoresistance and cu…