The Hartman effect in a one-dimensional photonic crystal containing a defect layer doped by three-level laddertype atoms is theoretically investigated for normal and oblique incidences. The influence of the relative phase of applied fields and the intensity of the coupling field on the Hartman effect is then discussed. We find that the Hartman effect can be switched from positive to negative (or vice versa) by adjusting the relative phase of applied fields and the intensity of the coupling field and by choosing the proper incident angle.
