Xie Zhi, Chen Limin
College of Mechanical and Electronic Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Nanomaterials (Basel). 2021 Oct 14;11(10):2707. doi: 10.3390/nano11102707.
Doping of foreign atoms may substantially alter the properties of the host materials, in particular low-dimension materials, leading to many potential functional applications. Here, we perform density functional theory calculations of two-dimensional InSe materials with substitutional doping of lanthanide atoms (Ce, Nd, Eu, Tm) and investigate systematically their structural, magnetic, electronic and optical properties. The calculated formation energy shows that the substitutional doping of these lanthanide atoms is feasible in the InSe monolayer, and such doping is more favorable under Se-rich than In-rich conditions. As for the structure, doping of lanthanide atoms induces visible outward movement of the lanthanide atom and its surrounding Se atoms. The calculated total magnetic moments are 0.973, 2.948, 7.528 and 1.945 μB for the Ce-, Nd-, Eu-, and Tm-doped systems, respectively, which are mainly derived from lanthanide atoms. Further band structure calculations reveal that the Ce-doped InSe monolayer has n-type conductivity, while the Nd-doped InSe monolayer has p-type conductivity. The Eu- and Tm-doped systems are found to be diluted magnetic semiconductors. The calculated optical response of absorption in the four doping cases shows redshift to lower energy within the infrared range compared with the host InSe monolayer. These findings suggest that doping of lanthanide atoms may open up a new way of manipulating functionalities of InSe materials for low-dimension optoelectronics and spintronics applications.
掺杂外来原子可能会显著改变主体材料的性质，特别是低维材料，从而带来许多潜在的功能应用。在此，我们对二维InSe材料进行了镧系原子（Ce、Nd、Eu、Tm）替代掺杂的密度泛函理论计算，并系统研究了它们的结构、磁性、电子和光学性质。计算得到的形成能表明，这些镧系原子的替代掺杂在InSe单层中是可行的，并且在富硒条件下比富铟条件下更有利。至于结构，镧系原子的掺杂导致镧系原子及其周围的硒原子明显向外移动。计算得到的Ce、Nd、Eu和Tm掺杂体系的总磁矩分别为0.973、2.948、7.528和1.945 μB，主要来源于镧系原子。进一步的能带结构计算表明，Ce掺杂的InSe单层具有n型导电性，而Nd掺杂的InSe单层具有p型导电性。发现Eu和Tm掺杂体系为稀磁半导体。与主体InSe单层相比，四种掺杂情况下计算得到的吸收光学响应在红外范围内显示出向较低能量的红移。这些发现表明，镧系原子的掺杂可能为低维光电子学和自旋电子学应用中操纵InSe材料的功能开辟一条新途径。
