论文标题
强烈的电子 - phonon耦合并预测2H-mo $ _ {2} $ n在双轴压力下揭示的MXENES的最高已知$ T_ {C} $
Strong electron-phonon coupling and predicted highest known $T_{c}$ of MXenes revealed in 2H-Mo$_{2}$N under biaxial stress
论文作者
论文摘要
这封信报告了意外强的电子 - phonon耦合（EPC）和最高的$ T_C $记录（$ \ $ \ $ 38 K），在双重压力下2H-MO $ _2 $ N中显示的MXENES中。首先，其优异的机械性能以37 GPA的理想强度和438 GPA的理想强度证明。随后，在动态稳定的应变范围内阐明了EPC和相应的$ T_C $。对于无应变的2H-MO $ _2 $ N，EPC常数（$λ$）和$ T_C $分别为1.3和22.7 K。此$ T_C $高于2H-MO $ _2 $ C（4.3 K），1T-MO $ _2 $ n（16.8 K）和其他原始MXENES的$ T_C $。当受到压缩和拉伸应力时，该材料在$λ$和$ t_c $中表现出显着的增强。显而易见的EPC，$λ$超过2.0的$λ$以-4％，-2.5％和5％的菌株发生，分别为$ t_c $ s，分别为37.8、35.4和28.9 K。我们的发现表明，电子带的应变依赖性特征和能级在增强EPC中起着至关重要的作用。此外，基于晶格振动，阐明了Mo $ _2 $ N的EPC较强的EPC。因此，这项工作铺平了一种使用调谐原子食谱和应变依赖性工程设计2D超导材料的实用方法。
This letter reports the unexpectedly strong electron-phonon coupling (EPC) and the highest $T_c$ record ($\approx$ 38 K) among the MXenes revealed in the 2H-Mo$_2$N under biaxial stress. At first, its excellent mechanical properties are demonstrated with ideal strength of 37 GPa and elastic modulus of 438 GPa. Subsequently, EPC and corresponding $T_c$ are elucidated upon the dynamically stable range of strain. For strain-free 2H-Mo$_2$N, the EPC constant ($λ$) and $T_c$ are 1.3 and 22.7 K, respectively. This $T_c$ is higher than those of 2H-Mo$_2$C (4.3 K), 1T-Mo$_2$N (16.8 K), and other pristine MXenes. The material exhibits remarkable enhancement in $λ$ and $T_c$ when subject to compressive and tensile stresses. The obvious strong EPC with $λ$ over 2.0 occurs at strains of -4%, -2.5%, and 5%, yielding $T_c$s of 37.8, 35.4, and 28.9 K, respectively. Our findings suggest that the strain-dependent feature and energy levels of electronic bands play an essential role in enhancing EPC. Moreover, the stronger EPC in Mo$_2$N compared with Mo$_2$C is clarified based on lattice vibrations. Therefore, this work paves a practical way for designing 2D superconducting materials using tuning atomic recipes and strain-dependent engineering.
