论文标题
关于单电子散射的重要性，单层二甲藻元中载体放松期间的载体散射和能量重量差异
On the importance of electron-electron and electron-phonon scatterings and energy renormalizations during carrier relaxation in monolayer transition-metal dichalcogenides
论文作者
论文摘要
基于$ \ it {ab \，\，Initio} $基于完全微观的多体方法，用于研究单层过渡金属二核化合物中的载体松弛动力学。使用密度函数理论计算带结构和波形函数以及声子能量和耦合矩阵元素。所得的偶极子和库仑矩阵元素在Dirac-Bloch方程中实现，以计算整个Brillouin区域的载流子和载波散射。结果表明，载流子散射导致在单一飞秒时间尺度上放松进入热的准Fermi分布。载体冷却和谷化过渡是通过在平时时间尺度上的声子散射介导的。强，密度依赖性的能量重量化被证明是山谷依赖性的。对于Mote $ _2 $，MOSE $ _2 $和MOS $ _2 $与$σ$和$λ$ side Valleys相比，与$ k $和$ k $ and $ k'$ valleys相比，使用职业的能量变化约为50 $ \％$。但是，对于逼真的载体密度，这些材料始终将其直接带盖保持在布里鲁因区域的$ K $点。
An $\it{ab \,\, initio}$ based fully microscopic many-body approach is used to study the carrier relaxation dynamics in monolayer transition-metal dichalcogenides. Bandstructures and wavefunctions as well as phonon energies and coupling matrix elements are calculated using density functional theory. The resulting dipole and Coulomb matrix elements are implemented in the Dirac-Bloch equations to calculate carrier-carrier and carrier-phonon scatterings throughout the whole Brillouin zone. It is shown that carrier scatterings lead to a relaxation into hot quasi-Fermi distributions on a single femtosecond timescale. Carrier cool down and inter-valley transitions are mediated by phonon scatterings on a picosecond timescale. Strong, density-dependent energy renormalizations are shown to be valley-dependent. For MoTe$_2$, MoSe$_2$ and MoS$_2$ the change of energies with occupation is found to be about 50$\%$ stronger in the $Σ$ and $Λ$ side valleys than in the $K$ and $K'$ valleys. However, for realistic carrier densities, the materials always maintain their direct bandgap at the $K$ points of the Brillouin zone.
