Interactions-controlled magnetotransport in two-dimensional massless-massive fermion mixtures
The presence of two types of holes, namely the Dirac holes and the massive holes, in a two-dimensional sample exposed to an external permanent magnetic field leads to the emergence of the temperature and magnetic field-dependent contribution to the resistivity due to their interactions. Taking a HgTe-based two-dimensional semimetal as a testbed, we develop a theoretical model describing the role of interactions between the degenerate massive and massless Dirac particles for the magnetoconductivity and resistivity in the presence of a classical magnetic field. If only the Dirac holes are present in the system, the magnetoconductivity acquires a finite interaction-induced contribution, which would vanish for the parabolic spectrum. It demonstrates $T^4\ln(1/T)$ behavior at low temperatures for short-range interhole interaction potential, and $T^2$-like behavior in the case of long-range interhole interaction potential. However, the magnetoresistivity and the Hall effect are not affected by the Dirac holes interparticle correlations in the lowest order of interparticle interaction. In contrast to this, the presence of two types of holes provides a finite contribution to the magnetoconductivity, magnetoresistivity, and the classical Hall effect resistivity. The temperature behavior of the magnetoconductivity here is $\sim T^2$ in the case of the short-range constant interparticle interaction potential and $T^2\ln(1/T)$ for the bare unscreened Coulomb interaction. A classically strong magnetic field suppresses the interaction-induced corrections to magnetoresistivity of massless-massive hole gas mixture.