标题： $α$-MoGe薄膜中超导性的不寻常厚度依赖性 显示英文标题

标题： The unusual thickness dependence of superconductivity in $α$-MoGe thin films

摘要： 薄层的$\alpha$-MoGe 在厚度低于30纳米时，$T_{c}$逐渐减少，当面电阻超过100$\Omega/\Box$时更为明显。 我们对一组$\alpha$-MoGe 薄膜进行了远红外透射和反射测量，以表征这种减弱的超导态。 我们的结果表明，在所有研究的薄膜中都存在一个能量间隙，其比值为$2\Delta_0/k_BT_{c} = 3.8 \pm 0.1$，略高于BCS值，尽管随着薄膜厚度的减小，转变温度显著降低。 材料特性遵循BCS-Eliashberg理论，除了在光学散射率中观察到的相干峰在较薄的超导样品中被强烈展宽外，其余均符合该理论。 在$2\Delta_0$处出现了光学质量重整化峰，这是首次被预测并观察到的。 显示英文摘要

摘要： Thin films of $\alpha$-MoGe show progressively reduced $T_{c}$'s as the thickness is decreased below 30 nm and the sheet resistance exceeds 100 $\Omega/\Box$. We have performed far-infrared transmission and reflection measurements for a set of $\alpha$-MoGe films to characterize this weakened superconducting state. Our results show the presence of an energy gap with ratio $2\Delta_0/k_BT_{c} = 3.8 \pm 0.1$ in all films studied, slightly higher than the BCS value, even though the transition temperatures decrease significantly as film thickness is reduced. The material properties follow BCS-Eliashberg theory with a large residual scattering rate except that the coherence peak seen in the optical scattering rate is found to be strongly smeared out in the thinner superconducting samples. A peak in the optical mass renormalization at $2\Delta_0$ is predicted and observed for the first time.