标题： Co(0001)/MoS2界面的电子结构及其在单层MoS2中电荷自旋注入的可能应用 显示英文标题

标题： Electronic structure of the Co(0001)/MoS2 interface, and its possible use for electrical spin injection in a single MoS2 layer

摘要： 从铁磁金属向基于过渡金属二硫属化物单层的二维半导体晶体进行高效的电荷自旋注入能力是使用这些材料的自旋电子学和谷电子学器件的前提条件。 在这里，通过基于密度泛函理论的第一性原理计算研究了hcp Co(0001)/MoS2界面的电子结构。 在优化原子坐标后的混合系统最低能量构型中，我们表明界面硫原子与一个、两个或三个钴原子共价结合。 在界面处观察到钴原子的自旋磁矩减小，同时硫原子表现出较小的磁化。 钼原子也具有较小的磁矩，可以为正值也可以为负值。 已经计算了由于界面处硫和钴原子之间的共价键引起的多数自旋和少数自旋电子的电荷转移，并讨论了这些界面电荷转移与MoS2层感应磁性性质之间的联系。 考虑自旋轨道耦合，计算了混合系统中多数自旋和少数自旋电子的能带结构和态密度。 我们证明，由于Co d轨道和S p轨道之间的杂化，与Co接触的MoS2变得金属。 对于这种MoS2的金属相，计算出费米能级处的自旋极化度绝对值为16%，这可能允许自旋注入到半导体MoS2单层通道中。 最后，研究了在Co结合的金属相中MoS2费米能级处的多数自旋和少数自旋电子波函数的对称性以及MoS2金属相和半导体相之间的边界方向，并讨论了它们对自旋注入到MoS2通道的影响。 显示英文摘要

摘要： The ability to perform efficient electrical spin injection from ferromagnetic metals into two-dimensional semiconductor crystals based on transition metal dichalcogenide monolayers is a prerequisite for spintronic and valleytronic devices using these materials. Here, the hcp Co(0001)/MoS2 interface electronic structure is investigated by first-principles calculations based on the density functional theory. In the lowest energy configuration of the hybrid system after optimization of the atomic coordinates, we show that interface sulfur atoms are covalently bound to one, two or three cobalt atoms. A decrease of the Co atom spin magnetic moment is observed at the interface, together with a small magnetization of S atoms. Mo atoms also hold small magnetic moments which can take positive as well as negative values. The charge transfers due to covalent bonding between S and Co atoms at the interface have been calculated for majority and minority spin electrons and the connections between these interface charge transfers and the induced magnetic properties of the MoS2 layer are discussed. Band structure and density of states of the hybrid system are calculated for minority and majority spin electrons, taking into account spin-orbit coupling. We demonstrate that MoS2 bound to the Co contact becomes metallic due to hybridization between Co d and S p orbitals. For this metallic phase of MoS2, a spin polarization at the Fermi level of 16 % in absolute value is calculated, that could allow spin injection into the semiconducting MoS2 monolayer channel. Finally, the symmetry of the majority and minority spin electron wave functions at the Fermi level in the Co-bound metallic phase of MoS2 and the orientation of the border between the metallic and semiconducting phases of MoS2 are investigated, and their impact on spin injection into the MoS2 channel is discussed.