Enhancement of Superconductivity in Plumbene-Based Superstructure
Wan-Hsin Chen1*, Chin-Hsuan Chen2, Guan-Hao Chen1, Pratyay Amrit1, Fu-Xiang Rikudo Chen1, Pei-Jung Chen1, Chun-Kai Ku1, Chang-Tsan Lee1, Jia-Ying Li2, Wei-Chuan Chen2, Iwao Matsuda3, Chung-Yu Mou2, Chien-Te Wu1, Horng-Tay Jeng2, Shu-Jung Tang2, Chun-Liang Lin1
1Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
2Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
3Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
* Presenter:Wan-Hsin Chen, email:lucychen.ep05g@g2.nctu.edu.tw
Since several fascinating properties of graphene have been discovered, the discussion of honeycomb structure materials in the field of two-dimensional materials has increased dramatically. As an element of the carbon family, lead (Pb) also has a similar structure called plumbene [1]. Considering that plumbene is the heaviest element in graphene-like materials, it is expected to show the most significant spin-orbit coupling (SOC) effect. 2D superconductivity with strong SOC has been confirmed in ultrathin Pb films on Si [2]. Theoretical predictions indicate that the tuning buckling and spin-orbit couplings in two-dimensional materials may enhance the superconducting critical temperature [3, 4]. Accordingly, it is intriguing to investigate whether superconductivity exists in other plumbene-based superstructures.

In this work, we investigate a plumbene-based superstructure consisting of two elements, Pb and Au. By using scanning tunneling microscopy (STM) and temperature-dependent scanning tunneling spectroscopy (STS), we found a higher critical temperature (Tc) in this plumbene-based superstructure than the Pb. It strongly suggests that change of the Fermi surface induced by buckling and spin-orbit interaction modifies the density of states that enhances the superconducting critical temperature (Tc) in the plumbene-based superstructure.

[1] J. Yuhara et al., Adv. Mater. 31 1901017 (2019)
[2] H. Nam et al., PNAS 113 10513 (2016)
[3] B. Zhang et al., Physica E 130 114688 (2021).
[4] E. Cappelluti et al., Phys. Rev. Lett. 98 167002 (2007).

Keywords: scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), Superconductivity, Plumbene