Phase transitions at ν=5/2 in ZnO-based heterostructures

The ability to control the orbital degrees of freedom in high mobility two-dimensional electron systems could open the door to tuning novel phase transitions between strongly correlated states of matter. In these proceedings, we present magnetotransport data of MgZnO/ZnO-based two-dimensional electron systems to study the phase transitions at Landau filling nu = 5/2. A rich cascade of phase transitions is resolved as we modify the polarization of carriers between the N = 1 down arrow and 0 up arrow levels by rotating the sample within a magnetic field. These include a gapped fractional quantum Hall state in close proximity to compressible and anisotropic phases, providing evidence for a delicate competition of a manifold of correlated states that are present at fractional fillings, and whose nature is yet to be fully understood. Note: Contribution to proceedings of Physics at the Nanoscale 2018, in dedication to Professor Tapash Chakraborty.