Interface effect in Nb-Bi2Te3 hybrid structure
Interface effect in Nb-Bi2Te3 hybrid structure
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DOI：
10.1063/1.4824651
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发表时间：
2013-10
影响因子：
4
通讯作者：
Hongchao Liu;Hongtao He;Baikui Li;Shiguang Liu;Q. He;Gan Wang;I. Sou;Jiannong Wang
中科院分区：
文献类型：
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作者：
Hongchao Liu;Hongtao He;Baikui Li;Shiguang Liu;Q. He;Gan Wang;I. Sou;Jiannong Wang
在Bi_2 Te_3薄膜上制备了Nb条阵列。输运测量表明，在Nb超导转变温度以下，电阻出现上升。对应于这种电阻上升，零偏置附近的微分电阻峰和一个突出的负磁阻在低磁场观察。增加测量电流、温度和外加磁场可以抑制电阻上升、微分电阻峰值和负磁阻效应。我们解释了这些现象的Nb超导间隙和Andreev反射的抑制，由于在Nb-Bi_2 Te_3界面的低透明度引起的能量势垒效应。
An array of Nb strips was fabricated on a Bi2Te3 thin film. Transport measurements show that an upturn of the resistance occurs below the Nb superconducting transition temperature. Corresponding to this resistance upturn, a differential resistance peak around zero bias and a prominent negative magnetoresistance at low magnetic fields are observed. The resistance upturn, differential resistance peak, and negative magnetoresistance can be suppressed by increasing measurement current, temperature, and applied magnetic field. We explain these phenomena in terms of an energy barrier effect induced by the Nb superconducting gap and the suppression of Andreev reflection due to the low transparency at the Nb-Bi2Te3 interface.