Dynamical Stability and Superconductivity in Two-dimensional Nodal Line Semimetal CuSe and Cu2Si

• Published in: Journal of superconductivity and novel magnetism 2021-09, Vol.34 (9), p.2229-2237
• Main Authors: Wang, Xing, Chen, Jianyong
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Condensed Matter Physics; Magnetic Materials; Magnetism; Original Paper; Physics; Physics and Astronomy; Strongly Correlated Systems; Superconductivity
• ISSN: 1557-1939; 1557-1947
• DOI: 10.1007/s10948-021-05924-9

Driving topological nontrivial materials into superconductors is promising to realizing topological superconductors which lay the foundation towards fault-tolerant quantum computing. However, material realization so far is rare and less satisfied. Recently, two-dimensional topological nodal lines semimetal CuSe (Adv. Mater., 30 (2018) 1,707,055) and Cu 2 Si (Nat. Commun., 8 (2017) 1007) are successfully fabricated. Based on complete and reliable first-principle calculations, we predict that both CuSe and Cu 2 Si are intrinsic superconductors with transition temperature of 0.36 K and 1.54 K. For dynamic stability, spin–orbit coupling is essential to obtain positive phonon dispersion of free-standing CuSe. As a suitable substrate, graphene can not only preserve the nodal line and the electron–phonon coupling (EPC) but also substantially enhance the dynamical stability of CuSe. In addition, electron–electron correlation in CuSe enhances the EPC of E ' mode by a factor of 1.84. T c of Cu 2 Si decreases with the increasing of strains. The coexistence of superconductivity and nontrivial topology in Cu 2 Si and CuSe makes them a promising candidate for realizing topological superconductivity.