Two-dimensional (2D) topological superconductors not only provide a platform for exploring novel quantum physical phenomena but also play a significant role in the field of quantum computing. However, reports on 2D topological superconductors are quite scarce. Here, based on first-principles calculations, we study the superconductivity of a class of monolayer ${TM}_m{X}_n$ ($TM=\text{V}$, Nb, Ta; $X=\text{C}$, N; $m=2$, 3; $n=2$, 3; $m\ne n$) with $P\overline{6}m2$ (No. 187) and $P\overline{3}m1$ (No. 164) symmetries, referred to as $h\text{−}{TM}_m{X}_n$ (No. 187) and $t\text{−}{TM}_m{X}_n$ (No. 164), respectively. Among them, monolayer $h\text{−}{\mathrm{V}}_2{\mathrm{N}}_3$ is predicted to have the highest critical temperature $T_c$ as high as 38.4 K and a superconducting gap of about 9 meV. The superconductivity of monolayer $h\text{−}{\mathrm{V}}_2{\mathrm{N}}_3$ mainly originates from the strong coupling between conduction electrons from the V $3d$ and N $2p$ orbitals near the Fermi level and the low-frequency V- and N-related phonons. Moreover, nontrivial $Z_2$ band topology further demonstrates that monolayer $h\text{−}{\mathrm{V}}_2{\mathrm{N}}_3$ is a promising candidate for realizing 2D topological superconductivity. Our findings provide a robust platform to study the emergent phenomena in 2D topological superconductors.

Close

PrevNext

View figure in article

• Density of states
• Edge states
• Electrical properties
• Electronic structure
• Fermi surface
• First-principles calculations
• Spin-orbit coupling
• Superconductivity
• Topological materials
• Topological superconductors