Charge transport near pressure-induced antiferromagnetic quantum critical point in Magnéli-phase vanadium oxides

Abstract

Resistivity ( ρ) measurements on Magnéli phases V 7O 13 and V 8O 15 were performed under high pressures up to 3.5GPa. We have achieved a pressure-induced transition from an antiferromagnetic metal to a paramagnetic metal (PM) at critical pressures P c≈3.4 and 3.3 GPa for V 7O 13 and V 8O 15, respectively. The critical behavior of ρ( T) near P c turned out to be quite unusual in that no noticeable precursor effect was observed. This strongly contrasts with the canonical quantum critical point behavior observed in chemically modified systems such as Ni(S,Se) 2 and V 2O 3. We propose that the presence of two distinct Fermi surface segments is responsible for the observed unusual behaviors.