Takashi Uchihashi, National Institute for Materials Science, Japan
Room 410, 4th floor, Tsung-Dao LEE Library
Metal atomic layers on semiconductor surfaces constitute of a unique family of two-dimensional (2D) electron system. The recent discovery of superconductivity in this class of atomic-layer materials offers fresh opportunities for studying 2D superconductors [1-4]. In this talk I will report on two recent developments in our group on this type of atomic layer superconductors. First, we found that highly ordered layers of metal-phthalocyanine (MPc, M = Mn, Cu) molecules can modify the superconducting transition temperature (Tc) of the indium atomic layers on Si(111) surfaces in a controllable manner . This 2D system can be considered a molecule-based van der Waals heterostructures. Second, we performed magneto-transport measurements of the same atomic layer superconductor down to the lowest sample temperature of 900 mK and the largest magnetic field of 5 T. We found that the superconductivity is highly robust when a magnetic field was applied to the sample in an in-plane direction. The very likely influence of the Rashba effect will be discussed based on a spin-split Fermi surface of this atomic layer superconductor.
References  T. Zhang et al., Nat. Phys. 6, 104 (2010).  T. Uchihashi et al., Phys. Rev. Lett. 107, 207001 (2011) [Editor’s Suggestion and featured in Physics].  S. Yoshizawa, TU et al., Phys. Rev. Lett. 113, 247004 (2014) [Editor’s Suggestion and featured in Physics].  T. Uchihashi, Supercond. Sci. Technol. 30, 013002 (2017) [Topical Review].  S. Yoshizawa, TU et al., Nano Lett. 17, 2287 (2017).