de Haas-van Alphen Effect in Pressure-Induced Superconductor CrAs

We report on the first observation of the de Haas-van Alphen (dHvA) effect in CrAs under hydrostatic pressures of up to 2.2 GPa, exceeding the critical pressure P-c similar to 0.7 GPa, where the antiferromagnetic (helimagnetic) state is suppressed and the unconventional superconductivity emerges. The small Fermi surface (FS) with the dHvA frequency F of 220 T and the cyclotron effective mass m(c)* of 0.9 m(0) (m(0): rest mass of an electron) at ambient pressure disappears above P-c; instead, larger FSs with F of up to 3480T with relatively heavy m(c)* of up to 7.6m(0) were observed.