论文标题
应变诱导的半导体向MA2Z4双层中的金属转变
Strain-induced semiconductor to metal transition in MA2Z4 bilayers
论文作者
论文摘要
最近，已经制造了一种新型的二维分层材料MOSI2N4，它的层间相互作用，高强度和出色的稳定性是半导体的。我们从理论上系统地研究垂直应变对MA2Z4电子结构（M = Ti/Cr/Mo，A = Si，Z = N/P）双层的影响。以双层MOSI2N4为例，我们的第一个原理计算表明，随着垂直压缩应变的增加，其间接带隙会单调降低。在约22％的临界应变下，它经历了从半导体到金属的过渡。我们将其归因于状态在不同层中的相反能量转移，该层源自界面附近两个内部子层之间的不对称电荷转移引起的内置电场。在其他紧张的MA2Z4双层中观察到了与金属转变相似的半导体，并且估计的临界压力估计的临界压力与半导体过渡金属二进制基因源相同。在MA2Z4双层家族中观察到的金属转变的半导体为应变引起的电子性质工程提出了有趣的可能性。
Very recently, a new type of two-dimensional layered material MoSi2N4 has been fabricated, which is semiconducting with weak interlayer interaction, high strength, and excellent stability. We systematically investigate theoretically the effect of vertical strain on the electronic structure of MA2Z4 (M=Ti/Cr/Mo, A=Si, Z=N/P) bilayers. Taking bilayer MoSi2N4 as an example, our first principle calculations show that its indirect band gap decreases monotonically as the vertical compressive strain increases. Under a critical strain around 22%, it undergoes a transition from semiconductor to metal. We attribute this to the opposite energy shift of states in different layers, which originates from the built-in electric field induced by the asymmetric charge transfer between two inner sublayers near the interface. Similar semiconductor to metal transitions are observed in other strained MA2Z4 bilayers, and the estimated critical pressures to realize such transitions are within the same order as semiconducting transition metal dichalcogenides. The semiconductor to metal transitions observed in the family of MA2Z4 bilayers present interesting possibilities for strain-induced engineering of their electronic properties.
