Surface conduction and reduced electrical resistivity in ultrathin noncrystalline NbP semimetal

IF 45.8 1区综合性期刊 Q1 MULTIDISCIPLINARY SCIENCES

Science Pub Date : 2025-01-02 DOI:10.1126/science.adq7096

Asir Intisar Khan, Akash Ramdas, Emily Lindgren, Hyun-Mi Kim, Byoungjun Won, Xiangjin Wu, Krishna Saraswat, Ching-Tzu Chen, Yuri Suzuki, Felipe H. da Jornada, Il-Kwon Oh, Eric Pop

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Abstract

The electrical resistivity of conventional metals such as copper is known to increase in thin films as a result of electron-surface scattering, thus limiting the performance of metals in nanoscale electronics. Here, we find an unusual reduction of resistivity with decreasing film thickness in niobium phosphide (NbP) semimetal deposited at relatively low temperatures of 400°C. In films thinner than 5 nanometers, the room temperature resistivity (~34 microhm centimeters for 1.5-nanometer-thick NbP) is up to six times lower than the resistivity of our bulk NbP films, and lower than conventional metals at similar thickness (typically about 100 microhm centimeters). The NbP films are not crystalline but display local nanocrystalline, short-range order within an amorphous matrix. Our analysis suggests that the lower effective resistivity is caused by conduction through surface channels, together with high surface carrier density and sufficiently good mobility as the film thickness is reduced. These results and the fundamental insights obtained here could enable ultrathin, low-resistivity wires for nanoelectronics beyond the limitations of conventional metals.

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超薄非晶NbP半金属的表面导电性和降低电阻率

众所周知，由于电子表面散射，传统金属（如铜）的电阻率在薄膜中会增加，从而限制了金属在纳米级电子学中的性能。在这里，我们发现在相对较低的400°C温度下沉积的磷化铌（NbP）半金属的电阻率随着膜厚度的减少而不同寻常地降低。在厚度小于5纳米的薄膜中，室温电阻率（1.5纳米厚的NbP约为34微米厘米）比我们的体NbP薄膜的电阻率低6倍，低于相同厚度的传统金属（通常约为100微米厘米）。NbP薄膜不是结晶性的，而是在非晶态基质中显示出局部纳米晶、短程有序。我们的分析表明，较低的有效电阻率是由于通过表面通道传导，以及随着薄膜厚度的减小，表面载流子密度高和迁移率足够好。这些结果和在这里获得的基本见解可以使纳米电子学的超薄、低电阻率导线超越传统金属的限制。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Science 综合性期刊-综合性期刊

CiteScore

61.10

自引率

0.90%

发文量

审稿时长

2.1 months

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