论文标题
通过氢化增强MXENES的超导性
Enhancing superconductivity in MXenes through hydrogenation
论文作者
论文摘要
二维过渡金属碳化物和氮化物（MXENES）是一类新兴的原子上薄的超导体，它们的特性很容易通过表面功能化来定制。在这里，我们探讨了基于第一原理计算与Eliashberg理论相结合的第一原理计算，探索了氢气的使用来增强声子介导的超导性。我们首先证明了三种基于氢化的Mo-和W的三种不同结构模型的稳定性。对于氢化的Mo $ $ _2 $ n和w $ _2 $ n，获得了超过30 K的临界温度特别高的温度。发现了多种负责增强电子偶联的机制，即（i）氢诱导的宿主Mxene的声子频谱的变化，（ii）新兴的基于氢气的声子模式，（iii）从氢气转移从氢到mxene层，增强了在福音层的状态状态的密度。最后，我们证明了氢气原子还能够诱导不以原始形式的超导，例如NB $ _2 $ c的MXENES中的超导性。
Two-dimensional transition metal carbides and nitrides (MXenes) are an emerging class of atomically-thin superconductors, whose characteristics are highly prone to tailoring by surface functionalization. Here we explore the use of hydrogen adatoms to enhance phonon-mediated superconductivity in MXenes, based on first-principles calculations combined with Eliashberg theory. We first demonstrate the stability of three different structural models of hydrogenated Mo- and W-based MXenes. Particularly high critical temperatures of over 30 K are obtained for hydrogenated Mo$_2$N and W$_2$N. Several mechanisms responsible for the enhanced electron-phonon coupling are uncovered, namely (i) hydrogen-induced changes in the phonon spectrum of the host MXene, (ii) emerging hydrogen-based phonon modes, and (iii) charge transfer from hydrogen to the MXene layer, boosting the density of states at the Fermi level. Finally, we demonstrate that hydrogen adatoms are moreover able to induce superconductivity in MXenes that are not superconducting in pristine form, such as Nb$_2$C.
