  Energy spectrum of electrons (holes) doped into a two-dimensional
antiferromagnetic insulator is quantized in an external magnetic field of
arbitrary direction. A peculiar dependence of de Haas-van Alphen (dHvA) or
Shubnikov-de Haas (SdH) magneto-oscillation amplitudes on the azimuthal
in-plane angle from the magnetization direction and on the polar angle from the
out-of-plane direction is found, which can be used as a sensitive probe of the
antiferromagnetic order in doped Mott-Hubbard, spin-density wave (SDW), and
conventional band-structure insulators.
