Plasma-enhanced pulsed-laser deposition of single-crystalline Mo2C ultrathin superconducting films

Transition-metal carbides (TMCs) possess many intriguing properties and inspiring application potentials, and recently the study of a two-dimensional form of TMCs has attracted great attention. Herein, we report successful fabrication of continuous $\mathrm{M}{\mathrm{o}}_{2}\mathrm{C}$ ultrathin single-crystalline films at $700{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$ with an approach of plasma-enhanced pulsed-laser deposition. By sophisticated structural analyses, the $\mathrm{M}{\mathrm{o}}_{2}\mathrm{C}$ films are characterized as single crystal with a rarely reported face-centered cubic structure. In further electrical transport measurements, superconductivity observed in the $\mathrm{M}{\mathrm{o}}_{2}\mathrm{C}$ films demonstrates a typical two-dimensional feature, which is consistent with Berezinskii-Kosterlitz-Thouless transitions. Besides, large upper critical magnetic fields are discovered in this system. Our work offers an approach to grow large-area and high-quality TMCs at relatively low temperatures. This study may stimulate more related investigations on the synthesis, characterizations, and applications of two-dimensional TMCs.