论文标题
通过超导波动引起的Nernst信号中的幽灵和镜像场的分析
Analysis of the Ghost and Mirror Fields in the Nernst Signal Induced by Superconducting Fluctuations
论文作者
论文摘要
我们对从常规到非常规的超导体中的超导波动引起的北部信号进行了完整的分析。在较大的温度和磁场范围内获得了对NernST信号的波动贡献的封闭分析表达。我们将此表达式直接应用于NB $ _x $ si $ _ {1-x} $薄膜和uru $ _2 $ si $ _2 $超导体的实验测量。可用数据的磁场和温度依赖性都仅使用两个拟合参数，即超导温度$ t _ {\ mathrm {c0}} $和上临界场$ h _ {\ mathrm {c2}} $。获得的值与实验获得的值非常吻合。我们还从完整表达式中提取幽灵线（最大恒定温度或磁场信号），并将其与几个实验获得的曲线进行比较。我们的方法预测了幽灵关键场的线性温度依赖性远高于$ t _ {\ mathrm {c0}} $。在实验数据的错误中，确实在许多超导体中观察到了这种线性，远离$ t _ {\ mathrm {c0}} $。
We present a complete analysis of the Nernst signal due to superconducting fluctuations in a large variety of superconductors from conventional to unconventional ones. A closed analytical expression of the fluctuation contribution to the Nernst signal is obtained in a large range of temperature and magnetic field. We apply this expression directly to experimental measurements of the Nernst signal in Nb$_x$Si$_{1-x}$ thin films and a URu$_2$Si$_2$ superconductors. Both magnetic field and temperature dependence of the available data are fitted with very good accuracy using only two fitting parameters, the superconducting temperature $T_{\mathrm{c0}}$ and the upper critical field $H_{\mathrm{c2}}$. The obtained values agree very well with experimentally obtained values. We also extract the ghost lines (maximum of the Nernst signal for constant temperature or magnetic field) from the complete expression and also compare it to several experimentally obtained curves. Our approach predicts a linear temperature dependence for the ghost critical field well above $T_{\mathrm{c0}}$. Within the errors of the experimental data, this linearity is indeed observed in many superconductors far from $T_{\mathrm{c0}}$.
