Possibility of chiral-surface-state originated bulk quantum hall effect in η-mo4o11 crystal

Magnetotransport properties have been measured for quasi-two-dimensional oxide η-Mo4O11 at low temperatures 0.3–4.2 K in magnetic fields up to 10 T using both bulk contacts and edge contacts methods. In the former case, normal Shubnikov-de Haas oscillations are observed. In the latter case, the Hall resistivity ρH and transverse magnetoresistance along the c-axis exhibits clear plateaus and minima, respectively, while the longitudinal magnetoresistance along the a*-axis shows a profound peak around 9 T. At the plateaus ρH is quantized as, ρH(v)/ρH(v=2) = 2/v(v: filling facter), which suggests that a 2D chiral-surface-state appears near the bulky crystal edge.