QUANTUM OSCILLATIONS IN THE VORTEX STATE OF A TYPE-II SUPERCONDUCTOR

In the presence of many-body interactions the real and imaginary parts of the interaction self energy influence the dHvA frequency and ampli tude, respectively. Starting with the Green's function for electrons i n the superconducting mixed state close to H(c2), we derive an express ion for the dHvA effect in the presence of a superconducting order par ameter DELTA. We find that for a spherical Fermi surface the dHvA freq uency is unchanged from the normal state, but that the amplitude is re duced by an additional quasiparticle scattering rate proportional to D ELTA2(H, T).