Magnetotransport in heterostructures of transition metal dichalcogenides and graphene
Magnetotransport in heterostructures of transition metal dichalcogenides and graphene
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DOI：
10.1103/physrevb.96.125405
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发表时间：
2017-06
影响因子：
3.7
通讯作者：
Tobias Volkl;T. Rockinger;Martin Drienovsky;Kenji Watanabe;T. Taniguchi;D. Weiss;J. Eroms
中科院分区：
文献类型：
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作者：
Tobias Volkl;T. Rockinger;Martin Drienovsky;Kenji Watanabe;T. Taniguchi;D. Weiss;J. Eroms
我们使用范德华拾取技术来制造包含 WSe2(WS2) 和石墨烯的不同异质结构。异质结构通过等离子蚀刻构造，通过一维边缘接触接触，并沉积顶栅。对于石墨烯/WSe2/SiO2 样品，我们观察到类似于 12 000 cm(2) V-1 s(-1) 的迁移率。对这些样品进行的磁场相关电阻测量显示，在低磁场下电导率出现峰值。这种下降归因于自旋轨道耦合产生的弱反定域（WAL）效应。石墨烯封装在 WSe2(WS2) 和六方氮化硼之间的样品表现出更高的迁移率，高达 120 000 cm(2) V-1 s(-1)。然而，在这些样品中没有观察到 WAL 峰。我们将此归因于从扩散状态到准弹道状态的转变。在低磁场下会出现电阻峰值，我们将其归因于边界散射引起的尺寸效应。由于自旋和谷简并性的完全提升，完全封装样品中的舒布尼科夫-德哈斯振荡显示出所有整数填充因子。
We use a van der Waals pickup technique to fabricate different heterostructures containing WSe2(WS2) and graphene. The heterostructures were structured by plasma etching, contacted by one-dimensional edge contacts, and a top gate was deposited. For graphene/WSe2/SiO2 samples we observe mobilities of similar to 12 000 cm(2) V-1 s(-1). Magnetic-field-dependent resistance measurements on these samples show a peak in the conductivity at low magnetic fields. This dip is attributed to the weak antilocalization (WAL) effect, stemming from spin-orbit coupling. Samples where graphene is encapsulated between WSe2(WS2) and hexagonal boron nitride show a much higher mobility of up to similar to 120 000 cm(2) V-1 s(-1). However, in these samples noWAL peak can be observed. We attribute this to a transition from the diffusive to the quasiballistic regime. At low magnetic fields a resistance peak appears, which we ascribe to a size effect due to boundary scattering. Shubnikov-de Haas oscillations in fully encapsulated samples show all integer filling factors due to complete lifting of the spin and valley degeneracies.