Past Events

Abstract
 

Recently, negative longitudinal and positive in-plane transverse magnetoresistance have been observed in most topological Dirac/Weyl semimetals, and some other topological materials. Here a quantum theory of intrinsic magnetoresistance for three-dimensional Dirac fermions at a finite and uniform magnetic field B is presented. In a semiclassical regime, it is shown that the longitudinal magnetoresistance is negative and quadratic of a weak field B while the in-plane transverse magnetoresistance is positive and quadratic of B. The relative magnetoresistance is inversely quartic of the Fermi wave vector and only determined by the carrier density, irrelevant to the external scatterings in the weak scattering limit. This intrinsic anisotropic magnetoresistance is measurable in systems with lower carrier density and high mobility. Furthermore, the Shubnikov-de Haas oscillations have been intensively studied in topological materials, the phase shift is believed to be the topological part of the Berry phase in two dimensions, however, for three-dimensional case, we demonstrated that the phase shift is a function of the mobility and the magnetic field, which is useful for experimental data analysis.  

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