6 research outputs found
Revealing the band structure of ZrTe using Multicarrier Transport
The layered material ZrTe appears to exhibit several exotic behaviors
which resulted in significant interest recently, although the exact properties
are still highly debated. Among these we find a Dirac/Weyl semimetallic
behavior, nontrivial spin textures revealed by low temperature transport, and a
potential weak or strong topological phase. The anomalous behavior of
resistivity has been recently elucidated as originating from band shifting in
the electronic structure. Our work examines magnetotransport behavior in
ZrTe samples in the context of multicarrier transport. The results, in
conjunction with ab-initio band structure calculations, indicate that many of
the transport features of ZrTe across the majority of the temperature range
can be adequately explained by the semiclassical multicarrier transport model
originating from a complex Fermi surface.Comment: Main Text: 10 pages, 5 figures; Supporting Information: 10 pages, 7
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Gate-controlled conductance enhancement from quantum Hall channels along graphene p-n junctions
The formation of quantum Hall channels inside the bulk of graphene is studied using various contact and gate geometries. p-n junctions are created along the longitudinal direction of samples, and enhanced conductance is observed in the case of bipolar doping due to new conducting channels forming in the bulk, whose position, propagating direction and, in one geometry, coupling to electrodes are determined by the gate-controlled filling factor across the device. This effect could be exploited to probe the behavior and interaction of quantum Hall channels protected against uncontrolled scattering at the edges
New method of transport measurements on van der Waals heterostructures under pressure
The interlayer coupling, which has a strong influence on the properties of van der Waals heterostructures, strongly depends on the interlayer distance. Although considerable theoretical interest has been demonstrated, experiments exploiting a variable interlayer coupling on nanocircuits are scarce due to the experimental difficulties. Here, we demonstrate a novel method to tune the interlayer coupling using hydrostatic pressure by incorporating van der Waals heterostructure based nanocircuits in piston-cylinder hydrostatic pressure cells with a dedicated sample holder design. This technique opens the way to conduct transport measurements on nanodevices under pressure using up to 12 contacts without constraints on the sample at the fabrication level. Using transport measurements, we demonstrate that a hexagonal boron nitride capping layer provides a good protection of van der Waals heterostructures from the influence of the pressure medium, and we show experimental evidence of the influence of pressure on the interlayer coupling using weak localization measurements on a transitional metal dichalcogenide/graphene heterostructure