MXenes have emerged as one of the most promising members among the two-dimensional (2D) material family owing to their unique physical-chemical properties and outstanding application prospects. Here, we investigated the unique magnetic properties of TiC MXenes monolayer by means of the first-principles calculations combining with the Heisenberg spin Hamiltonian approach. A strain-induced reversible magnetic transition for the TiC monolayer could be found in our study. When the strain is applied to the TiC monolayer, the magnetic configuration of the TiC monolayer transforms from the A-type antiferromagnetic (A-AFM) phase to the ferromagnetic (FM) phase with the biaxial tensile strain larger than 6%. Furthermore, the transition from the A-AFM phase to the FM phase was found to be closely related with the change of the Ti and C atomic magnetic moments. The direct magnetic coupling between Ti and C atoms with the increased Ti and C magnetic moments is able to stabilize the structure due to the weakened superexchange interaction between Ti and C atoms under large tensile strain. This is the underlying driving force for the transition from the A-AFM phase to the FM phase. This work provides a promising pathway to better understand the existence of magnetic reversal behavior in the TiC MXenes monolayer and opens the door to future magnetic applications of MXenes.

中文翻译：

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MXene 纳米片中应变诱导可逆磁态转变的基本机制

MXenes因其独特的物理化学性质和突出的应用前景而成为二维（2D）材料家族中最有前途的成员之一。在这里，我们通过第一性原理计算结合海森堡自旋哈密顿方法研究了TiC MXenes单层的独特磁性。在我们的研究中可以发现 TiC 单层的应变诱导可逆磁转变。当对TiC单层施加应变时，TiC单层的磁构型从A型反铁磁（A-AFM）相转变为铁磁（FM）相，双轴拉伸应变大于6%。此外，发现从A-AFM相到FM相的转变与Ti和C原子磁矩的变化密切相关。由于在大拉伸应变下Ti和C原子之间的超交换相互作用减弱，Ti和C原子之间的直接磁耦合随着Ti和C磁矩的增加而能够稳定结构。这是从A-AFM阶段过渡到FM阶段的潜在驱动力。这项工作为更好地理解 TiC MXenes 单层中磁反转行为的存在提供了一条有前途的途径，并为 MXenes 未来的磁性应用打开了大门。