arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1209.2965cond-mat.str-elcond-mat.supr-con
收藏

磁场诱导InO $_x$薄膜金属态零温超导配对的微波光谱证据

Microwave Spectroscopy Evidence of Superconducting Pairing in the Magnetic-Field-Induced Metallic State of InO$_x$ Films at Zero Temperature

Wei Liu, LiDong Pan, Jiajia Wen, Minsoo Kim, G. Sambandamurthy, N. P. Armitage

摘要:

我们研究了二维低无序非晶InO $_x$薄膜在0.05 ~ 16 GHz频率范围内的场调谐量子相变。在零温度极限下,AC数据与从超导体到金属而不是直接过渡到绝缘体的情况一致。介入的金属相是不寻常的,具有小但有限的电阻,其远小于在最低测量温度下的正常状态薄层电阻。此外,它表现出短的长度和时间尺度上的超导响应,而全球超导性被破坏。我们提出的证据表明,真正的量子临界点,这种二维超导体金属过渡位于远低于传统定义的临界场$B_{cross}$,其中不同的磁电阻等温线交叉对方的字段$B_{sm}$。在低频极限处的超流刚度和来自过渡区两侧的超导波动频率都在B $\approx B_{sm}$处消失。有限频率超流体刚度在$B_{cross}$中幸存的证据缺乏,这意味着$B_{cross}$是一个交叉点,在该交叉点之上,超导涨落对直流和交流测量的贡献消失。

英文摘要:

We investigate the field tuned quantum phase transition in a 2D low-disorder amorphous InO$_x$ film in the frequency range of 0.05 to 16 GHz employing microwave spectroscopy. In the zero temperature limit, the AC data are consistent with a scenario where this transition is from a superconductor to a metal instead of a direct transition to an insulator. The intervening metallic phase is unusual with a small but finite resistance that is much smaller than the normal state sheet resistance at the lowest measured temperatures. Moreover, it exhibits a superconducting response on short length and time scales while global superconductivity is destroyed. We present evidence that the true quantum critical point of this 2D superconductor metal transition is located at a field $B_{sm}$ far below the conventionally defined critical field $B_{cross}$ where different isotherms of magnetoresistance cross each other. The superfluid stiffness in the low frequency limit and the superconducting fluctuation frequency from opposite sides of the transition both vanish at B $\approx B_{sm}$. The lack of evidence for finite-frequency superfluid stiffness surviving $B_{cross}$ signifies that $B_{cross}$ is a crossover above which superconducting fluctuations make a vanishing contribution to DC and AC measurements.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑