10月25日 物理学院奚啸翔教授学术报告：二维NbSe2中的超导电性和电荷密度波

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 [1,2]. 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 field in atomically thin NbSe2 superconductors significantly exceeds the Pauli paramagnetic limit. We will discuss possible mechanisms for these phenomena and briefly report electrical tuning of the collective electronic orders in this 2D metal [3].