Spin polarized hole magneto-transport at low filling factors in monolayer WSe₂

Challenges associated with the quality of electrical contacts in semiconducting transition metal dichalcogenides have hampered the progress of transport studies, especially at low temperature and in the low carrier density regime.

Here, we first present a device structure for achieving low resistive ohmic contacts that relies on the independent tunability of the carrier density in the contact region. We demonstrate that these low resistive ohmic contacts survive at temperatures as low as 10 mK and can successfully be used in transport measurements to probe a channel region down to the low carrier density regime.

We then report magneto-transport measurements of a monolayer tungsten diselenide (WSe₂) heterostructure performed in perpendicular magnetic fields up to 8 T. We discuss the appearance of a Landau fan diagram in which we observe fully spin polarized hole transport at low filling factors all the way down to ν = 1. Finally, we discuss the behaviour of the Landau fan diagram at higher densities, reflecting spin-orbit coupling effects in monolayer WSe₂.