题目：二维NbSe₂中的超导电性和电荷密度波

报告人：奚啸翔 教授

                 南京大学物理学院

时间：2018年1月24日上午10:00

地点：国家脉冲强磁场科学中心C204

报告摘要：

Atomically thin van der Waals materials have emerged as a frontier for both fundamental physics and device applications. Although novel single-particle and excitonic properties have been extensively studied, the collective electron phenomena in these materials remain less well understood. In this talk, we will discuss superconductivity and charge-density-wave (CDW) order in atomically thin group-V transition metal dichalcogenide NbSe₂ down to the monolayer limit. Electrical transport measurements show that the superconducting transition temperature decreases monotonically with reducing the layer thickness. The temperature dependent Raman scattering, on the other hand, shows enhanced CDW order as the sample thickness reduces. Magneto-transport measurements further reveal that the in-plane upper critical fields in atomically thin NbSe₂ superconductors significantly exceed the Pauli paramagnetic limit. We will discuss possible mechanisms for these phenomena and electrical tuning of the superconductivity and CDW in this 2D metal.

参考文献：

[1] X. Xi, L. Zhao, Z. Wang, H. Berger, L. Forró, J. Shan, and K. F. Mak, "Strongly enhanced charge-density-wave order in monolayer NbSe₂," Nature Nanotech. 10, 765 (2015).

[2] X. Xi, Z. Wang, K. T. Law, H. Berger, L. Forró, J. Shan, and K. F. Mak, "Evidence of Ising pairing in superconducting monolayer NbSe₂," Nature Phys. 12, 139 (2016).

[3] X. Xi, H. Berger, L. Forró, J. Shan, and K. F. Mak, "Gate tuning of electronic phase transitions in two-dimensional NbSe₂," Phys. Rev. Lett. 117, 106801 (2016).

报告人简介：

奚啸翔，南京大学物理学院教授。2007年本科毕业于南京大学。2011年获美国佛罗里达大学物理学博士学位。2012至2014年于美国布鲁克海文国家实验从事博士后研究。2014至2016年为美国宾夕法尼亚州立大学助理研究员。目前主要研究方向为二维关联电子材料的物理性质。

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