2D transport and weak antilocalization effect in topological semimetal PtBi2 nanoflakes

The striking anisotropic magnetoresistance and linear magnetoresistance observed in topological semimetals have attracted immense attention owing to their potential in magnetoresistance devices. We investigated the magnetotransport properties of trigonal layered topological semimetal PtBi2. Bulk PtBi2 exhibited quadratic magnetoresistance, whereas nanoflakes exhibited linear and non-saturated magnetoresistance. We attribute the linear magnetoresistance in the nanoflake sample primarily to the disorder-induced guiding center magnetoresistance. Furthermore, a distinct weak antilocalization effect was observed in the PtBi2 nanoflakes; the temperature-dependent phase coherence length extracted from the weak antilocalization agrees with the strong electron–electron scattering in the nanoflakes. Further experimental results and analysis indicate the presence of a 2D transport channel in the PtBi2 nanoflakes. This finding provides a potential pathway for applications in versatile electronic devices.