Spin transport in high-mobility graphene on WS2 substrate with electric-field tunable proximity spin-orbit interaction
Spin transport in high-mobility graphene on WS2 substrate with electric-field tunable proximity spin-orbit interaction
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具有电场可调邻近自旋轨道相互作用的 WS2 基底上高迁移率石墨烯的自旋输运
DOI：
10.1103/physrevb.97.045414
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发表时间：
2017
影响因子：
3.7
通讯作者：
B. Wees
中科院分区：
文献类型：
--
作者：
S. Omar;B. Wees
石墨烯负载在过渡金属二硫属化物衬底上提供了一个新的平台来研究在衬底诱导的自旋轨道耦合存在下石墨烯中的自旋输运，同时保持其固有的电荷输运性质。我们报告了第一个非局域自旋输运测量石墨烯完全支持在3.5 nm厚的二硫化钨（WS 2）基板，并从顶部封装与8 nm厚的六方氮化硼层。对于迁移率高达16 000 cm 2 V−1 s−1的石墨烯，我们在电子和空穴掺杂状态下测量了几乎恒定的自旋信号，与底层WS 2衬底的导电状态无关，这排除了WS 2的自旋吸收作用。WS 2上石墨烯中电子的自旋弛豫时间τs从同一芯片上SiO2上石墨烯中的τs ~ 800 ps大幅降低至~ 10 ps。在量子磁电阻测量中，τs沿着可检测到的弱反定域特征的强抑制是石墨烯中WS 2诱导的自旋轨道耦合（SOC）的明显效应。通过在封装区域中施加顶栅电压，我们将电场调制为1 V/nm，将τs几乎改变了四倍，这表明平面内Rashba SOC的电场控制。此外，通过τs的载流子密度依赖性，我们还确定了石墨烯-WS 2界面处空穴掺杂制度中的D 'yakonov-Perel'型机制的指纹。
Graphene supported on a transition metal dichalcogenide substrate offers a novel platform to study the spin transport in graphene in the presence of a substrate-induced spin-orbit coupling while preserving its intrinsic charge transport properties. We report the first nonlocal spin transport measurements in graphene completely supported on a 3.5-nm-thick tungsten disulfide (WS2) substrate, and encapsulated from the top with an 8-nm- thick hexagonal boron nitride layer. For graphene, having mobility up to 16 000 cm2 V−1 s−1, we measure almost constant spin signals both in electron and hole-doped regimes, independent of the conducting state of the underlying WS2 substrate, which rules out the role of spin-absorption by WS2. The spin-relaxation time τs for the electrons in graphene-on-WS2 is drastically reduced down to ∼10 ps from τs ∼ 800 ps in graphene-on-SiO2 on the same chip. The strong suppression of τs along with a detectable weak antilocalization signature in the quantum magnetoresistance measurements is a clear effect of the WS2 -induced spin-orbit coupling (SOC) in graphene. Via the top-gate voltage application in the encapsulated region, we modulate the electric field by 1 V/nm, changing τs almost by a factor of four, which suggests electric-field control of the in-plane Rashba SOC. Further, via the carrier-density dependence of τs, we also identify the fingerprints of the D’yakonov-Perel’ type mechanism in the hole-doped regime at the graphene-WS2 interface.
影响因子：
3.7
作者：
Gmitra, Martin;Fabian, Jaroslav
通讯作者：
Fabian, Jaroslav
影响因子：
3.7
作者：
Gmitra, M.;Konschuh, S.;Fabian, J.
通讯作者：
Fabian, J.