Magnetic field dependent Dirac point in Bi1-xSbx alloys: magnetoresistance and thermoelectric properties.

Bi1-xSbx alloys with varying Sb concentration have bands that at x≈5 have a Dirac dispersion with the Dirac point at the L-point of the Brillouin zone. In strong magnetic fields, this Dirac point is theoretically expected to split into two Weyl points. This talk will present experimental magnetic field dependent transport properties of Bi1-xSbx alloys with varying Sb concentration. Field-dependence of thermoelectric properties, including thermopower, Nernst effect, Hall effect, resistivity, and thermal conductivity, at different Sb concentrations will be presented. Interestingly, a strong negative longitudinal magnetoresistance is observed at the composition and field where the Weyl points are expected to appear.