Rai D P, Vu Tuan V, Laref Amel, Hossain Md Anwar, Haque Enamul, Ahmad Sohail, Khenata R, Thapa R K
Physical Sciences Research Center (PSRC), Department of Physics, Pachhunga University College Aizawl-796001 India.
Division of Computational Physics, Institute for Computational Science, Ton Duc Thang University Ho Chi Minh City Vietnam
RSC Adv. 2020 May 19;10(32):18830-18840. doi: 10.1039/d0ra02585b. eCollection 2020 May 14.
This paper focuses on the electronic and thermoelectric properties of monolayer MoS. Here, we have examined the structure of MoS, in which the hole in the center of the hexagonal cage is considered as a void atom, termed 1H-MoS. Density functional theory (DFT) employing the generalized gradient approximation (GGA) and spin-orbit coupling (SOC) has been used for all calculations. Incorporation of SOC resulted in a significant change in the profile of the band energy, specifically the splitting of the valence band maximum (VBM) into two sub-bands. The "split-off" energy is found to be ∼20.6 meV. The reduction of the band gap with SOC is a prominent feature at the K-K location in the Brillouin zone. The band gap calculated with the GGA is ∼1.75 eV. However, on implementation of SOC, the GGA band gap was reduced to ∼1.68 eV. The frequency-dependent phonon dispersion curve was obtained to analyse the thermodynamical stability. 1H-MoS is found to be thermodynamically stable with no imaginary frequency. We report a low value of lattice thermal conductivity ( ) and low electron effective masses, which are desirable for potential applications in thermoelectric devices.
本文聚焦于单层二硫化钼（MoS）的电学和热电性质。在此，我们研究了二硫化钼的结构，其中六角形笼中心的空穴被视为一个空穴原子，称为1H - MoS。所有计算均采用了广义梯度近似（GGA）和自旋轨道耦合（SOC）的密度泛函理论（DFT）。引入SOC导致能带能量分布发生显著变化，特别是价带顶（VBM）分裂为两个子带。发现“分裂”能量约为20.6毫电子伏特。在布里渊区的K - K位置，带隙随SOC的减小是一个显著特征。用GGA计算的带隙约为1.75电子伏特。然而，在实施SOC后，GGA带隙减小到约1.68电子伏特。获得了频率相关的声子色散曲线以分析热力学稳定性。发现1H - MoS在热力学上是稳定的，没有虚频率。我们报道了较低的晶格热导率值和低电子有效质量，这对于热电设备的潜在应用是有利的。
