Yokoi Masahiko, Fujiwara Satoshi, Kawamura Tomoya, Arakawa Tomonori, Aoyama Kazushi, Fukuyama Hiroshi, Kobayashi Kensuke, Niimi Yasuhiro
Department of Physics, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan.
Center for Spin Research Network, Osaka University, Toyonaka 560-8531, Japan.
Sci Adv. 2020 Aug 21;6(34). doi: 10.1126/sciadv.aba1377. Print 2020 Aug.
We report a negative resistance, namely, a voltage drop along the opposite direction of a current flow, in the superconducting gap of NbSe thin films under the irradiation of surface acoustic waves (SAWs). The amplitude of the negative resistance becomes larger by increasing the SAW power and decreasing temperature. As one possible scenario, we propose that soliton-antisoliton pairs in the charge density wave of NbSe modulated by the SAW serve as a time-dependent capacitance in the superconducting state, leading to the dc negative resistance. The present experimental result would provide a previously unexplored way to examine nonequilibrium manipulation of the superconductivity.
我们报道了在表面声波（SAW）辐照下，NbSe薄膜超导能隙中存在负电阻，即电流流动方向相反的电压降。通过增加SAW功率和降低温度，负电阻的幅度会变大。作为一种可能的情况，我们提出，由SAW调制的NbSe电荷密度波中的孤子 - 反孤子对在超导态下充当随时间变化的电容，从而导致直流负电阻。目前的实验结果将为研究超导性的非平衡操纵提供一种前所未有的方法。
