相关论文: Robust Helical Edge Transport in Quantum Spin Hall…
Spin-valley locking in the band structure of monolayers of MoS$_2$ and other group-VI dichalcogenides has attracted enormous interest, since it offers potential for valleytronic and optoelectronic applications. Such an exotic electronic…
The co-presence of multiple Dirac bands in few-layer graphene leads to a rich phase diagram in the quantum Hall regime. Using transport measurements, we map the phase diagram of BN-encapsulated ABA-stacked trilayer graphene as a function…
HgTe quantum wells and surfaces of three-dimensional topological insulators support Dirac fermions with a single-valley band dispersion. In the presence of disorder they experience weak antilocalization, which has been observed in recent…
We explore the scattering of Dirac electrons in a double-gated topological insulator in the presence of magnetic proximity effects and warped surface states. It is found that a magnetic field can shift the Dirac cone in momentum space and…
We investigate spin transport of heavy holes in III-V semiconductor quantum wells in the presence of spin-orbit coupling of the Rashba type due to structure-inversion asymmetry. Similarly to the case of electrons, the longitudinal spin…
The quantum spin Hall (QSH) state, observed in a zero magnetic field in HgTe quantum wells, respects the time-reversal symmetry and is distinct from quantum Hall (QH) states. We show that the QSH state persists in strong quantizing fields…
Massive Dirac fermions break the chiral symmetry explicitly and also make the Berry curvature of the band structure non-Abelian. By utilizing the Green's function technique, we develop a microscopic theory to establish a set of quantum…
The quantum spin Hall (QSH) state is a genuinely new state of matter characterized by a non-trivial topology of its band structure. Its key feature is conducting edge channels whose spin polarization has potential for spintronic and quantum…
Here we report the possible signature of Dirac fermions in the magnetoresistance, Hall resistivity and magnetothermopower of LaAgSb$_2$. The opposite sign between Hall resistivity and Seebeck coefficient indicates the multiband effect.…
Quantum spin Hall devices with edges much longer than several microns do not display ballistic transport: that is, their measured conductances are much less than $e^2/h$ per edge. We imaged edge currents in InAs/GaSb quantum wells with long…
We experimentally investigate spin-polarized electron transport between two ferromagnetic contacts, placed at the edge of a two-dimensional electron system with band inversion. The system is realized in a narrow (8~nm) HgTe quantum well,…
We report transport measurements in a single edge channel of an InAs/GaSb quantum spin Hall insulator, where the conduction occurs through only one pair of counterpropagating edge modes. By using a specific sample design involving highly…
Theoretical investigation of Dirac electrons in electrically modulated graphene under perpendicular magnetic field B is presented. We have carried out a detailed study of modulation effect on Dirac electrons, which determine its electrical…
We experimentally study electron transport between edge states in the fractional quantum Hall effect regime. We find an anomalous increase of the transport across the 2/3 incompressible fractional stripe in comparison with theoretical…
Low energy excitation of surface states of a three-dimensional topological insulator (3DTI) can be described by Dirac fermions. By using a tight-binding model, the transport properties of the surface states in a uniform magnetic field is…
Surfaces of topological insulators host a new class of states with Dirac dispersion and helical spin texture. Potential quantum computing and spintronic applications using these states require manipulation of their electronic properties at…
We address the electron transport characteristics in bulk half-Heusler alloys with their compositions tuned to the borderline between topologically nontrivial semi-metallic and trivial semiconducting phases. The precise first-principles…
Topological insulators insulate in the bulk but exhibit robust conducting edge states protected by the topology of the bulk material. Here, we design a colloidal topological insulator and demonstrate experimentally the occurrence of edge…
We predict that in InAs/GaSb nanowires with an inverted band alignment a transverse electric field induces a collapse of the hybridization gap, and a semimetal phase occurs. We use a self-consistent k.p approach and an adapted…
We investigate new properties of the Dirac electrons in the finite graphene sample under perpendicular magnetic field that emerge when an in-plane electric bias is also applied. The numerical analysis of the Hofstadter spectrum and of the…