Suppression of scattering in quantum confined 2D helical Dirac systems

Article

关键词: TOPOLOGICAL INSULATOR NANORIBBONS;    CARBON NANOTUBES;    BACK SCATTERING;    GRAPHENE;    TRANSPORT;    FERMIONS;    SURFACE;    ABSENCE;   

DOI  :  10.1103/PhysRevB.97.075401

来源: SCIE

【 摘 要 】

Transport properties of helical Dirac fermions in disordered quantum wires are investigated in the large energy limit. In the quasiballistic regime, the conductance and the Fano factor are sensitive to disorder only when the Fermi energy is close to an opening of a transverse mode. In the limit of a large number of transverse modes, transport properties are insensitive to the geometry of the nanowire or the nature and strength of the disorder but, instead, are dominated by the properties of the interface between the ohmic contact and the nanowire. In the case of a heavily doped Dirac metallic contact, the conductance is proportional to the energy with an average transmission T = pi/4 and a Fano factor of F similar or equal to 0.13. Those results can be generalized to a much broader class of contacts, the exact values of T and F depending on the model used for the contacts. The energy dependence of Aharonov-Bohm oscillations is determined, revealing a damped oscillatory behavior and phase shifts due to the one-dimensional subband quantization and which are not the signature of the nontrivial topology.

【 授权许可】

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