论文标题
双层石墨烯中弱抗钙化的违反直觉依赖性/wse $ _2 $异构结构
Counterintuitive gate dependence of weak antilocalization in bilayer graphene/WSe$_2$ heterostructures
论文作者
论文摘要
最近在双层石墨烯/过渡金属二核苷（BLG/TMDC）异质结构中预测了接近诱导的自旋轨道耦合的强栅极控制，因为可以轻松地在两个石墨烯层之间移动电荷载体，并且其中只有一个与TMDC紧密接触。可以通过低场磁转运测量中的弱抗静电（WAL）来探测自旋轨道耦合的存在。当这种异质结构中的自旋轨道分裂随着平面电气位移$ \ bar d $的增加而增加时，一个直觉上的人会期望可见性的提高。我们的实验表明事实并非如此。取而代之的是，我们观察到$ \ bar d = 0 $的最大WAL可见性。这种违反直觉行为源于石墨烯中WAL对对称和反对称自旋寿命的复杂依赖性，分别是由山谷和Rashba术语引起的。我们的观察结果是通过计算$ 8 \ times 8 $ blg/tmdc模型的旋转进动和自旋寿命来确认的。
Strong gate control of proximity-induced spin-orbit coupling was recently predicted in bilayer graphene/transition metal dichalcogenides (BLG/TMDC) heterostructures, as charge carriers can easily be shifted between the two graphene layers, and only one of them is in close contact to the TMDC. The presence of spin-orbit coupling can be probed by weak antilocalization (WAL) in low field magnetotransport measurements. When the spin-orbit splitting in such a heterostructure increases with the out of plane electric displacement field $\bar D$, one intuitively expects a concomitant increase of WAL visibility. Our experiments show that this is not the case. Instead, we observe a maximum of WAL visibility around $\bar D=0$. This counterintuitive behaviour originates in the intricate dependence of WAL in graphene on symmetric and antisymmetric spin lifetimes, caused by the valley-Zeeman and Rashba terms, respectively. Our observations are confirmed by calculating spin precession and spin lifetimes from an $8\times 8$ model Hamiltonian of BLG/TMDC.
