2025/04/29 by Xiong, Si-Yi, Jiang, Peng, Wang, Yiming +1
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Superconductivity (cond-mat.supr-con)
paper · doi:10.48550/arxiv.2504.20868
The exploration of the superconductivity in two-dimensional materials has garnered significant attention due to their promising low-power applications and fundamental scientific interest. Here, we report some novel stable non-van der Waals NbxNx+1 (x = 1-4) monolayers derived from the NbN bulk exfoliated along the (001) plane, as identified through first-principles calculations. Among these monolayers, Nb2N3, which crystallizes in the P 6 m2 symmetry, stands out with an exceptional superconducting transition temperature of 77.8 K, setting a new high-Tc benchmark for two-dimensional transition metal nitrides and binary compounds. Our detailed analysis reveals that the strong superconductivity in Nb2N3 is driven by phonon modes dominated by N vibrations, with significant electron-phonon coupling contributions from N-p and Nb-d electronic states. Using the anisotropic Migdal-Eliashberg framework, we further determine the two-gap nature of the superconductivity in the Nb2N3 monolayer, characterized by pronounced electron-phonon coupling and anisotropic energy gaps. These results advance our understanding of superconductivity in 2D transition metal nitride and highlight their potential for nanoscale superconducting applications.