Comprehensive delineation of the anomalous magnetotransport regime in α-(BEDT-TTF)2MHg(SCN)4 (M = K, Tl)

We present pulsed-field magnetotransport measurements of α-(BEDT-TTF) 2 MHg(SCN)4 (M = K, Tl), covering fields B of up to 60 T and temperatures down to T = 500 mK. Interplane magnetoresistance and Hall-potential oscillations have been used to map the anomalous magnetotransport phenomena formerly attributed to the quantum Hall effect and chiral Fermi liquids. The effects occur in a region of B - T space suggestive of the formation of an exotic groundstate which depends on sample quality.