Electronic transport mechanisms in a thin crystal of the Kitaev candidate α-RuCl3 probed through guarded high impedance measurements

alpha-RuCl3 is considered to be the top candidate material for the experimental realization of the celebrated Kitaev model, where ground states are quantum spin liquids with interesting fractionalized excitations. It is, however, known that additional interactions beyond the Kitaev model trigger in alpha-RuCl3 a long-range zigzag antiferromagnetic ground state. In this work, we investigate a nanoflake of alpha-RuCl3 through guarded high impedance measurements aimed at reaching the regime where the system turns into a zigzag antiferromagnet. We investigated a variety of temperatures (1.45-175 K) and out-of-plane magnetic fields (up to 11 T), finding a clear signature of a structural phase transition at approximate to 160 K as reported for thin crystals of alpha-RuCl3, as well as a thermally activated behavior at temperatures above approximate to 30 K, with a characteristic activation energy significantly smaller than the energy gap that we observe for alpha-RuCl3 bulk crystals through our angle resolved photoemission spectroscopy (ARPES) experiments. Additionally, we found that below approximate to 30 K, transport is ruled by Efros-Shklovskii variable range hopping (VRH). Most importantly, our data show that below the magnetic ordering transition known for bulk alpha-RuCl3 in the frame of the Kitaev-Heisenberg model (approximate to 7 K), there is a clear deviation from VRH or thermal activation transport mechanisms. Our work demonstrates the possibility of reaching, through specialized high impedance measurements, the thrilling ground states predicted for alpha-RuCl3 at low temperatures in the frame of the Kitaev-Heisenberg model and informs about the transport mechanisms in this material in a wide temperature range.