Anomalous magneto-transport at low-density in a quasi-1d conductor

Among the various 2D magnetic semiconductors that have been recently discovered and investigated, CrSBr has shown unexpected transport properties under field-effect doping. In particular, the absence of Hall effect and a large anisotropy of the conductivity indicate quasi-1D behavior and possibly strong disorder [1].

Here, we study the field- and temperature-dependent longitudinal and transverse conductivities in a 2D anisotropic tight-binding model (t_⊥<?), where the dissipation is described by a local (i.e., momentum-independent) self-energy Σ. Using the Kubo formalism, we calculate numerically the conductivity tensor up to second order in the field. This model allows one to describe the crossover from a regime of coherent anisotropic transport when ∑ < t_⊥ to a quasi-1D regime with incoherent transport along one direction when t_⊥ < ∑ < t_?. Furthermore, it allows us to explore a low-density regime that has not been much studied so far, where the chemical potential lies below the band and, when k_BT < Σ, the metallicity stems from spectral-weight broadening due to the self-energy rather than thermal excitation of carriers.

[1] W. Fan et al., Adv. Mater. 2022, 2109759 (2022)