We show that the photoluminescence (PL) intensities of the interband transitions between the electron and hole Landau levels ${(n}_e{,n}_h=0,1,\dots )$ in a perpendicular magnetic field $B_{\perp }$ are modulated strongly by a superimposed in-plane field $B_{\parallel }$ in type-II quantum wells due to electron-hole separation: $B_{\parallel }$ suppresses the intensities of the $n_e\to n_h{=n}_e$ diagonal transitions initially and generates $n_e\to n_h\ne n_e$ off-diagonal transitions that are forbidden at $B_{\parallel }=0.\mathrm{}$ The intensities oscillate at higher $B_{\parallel }.$ An additional electric field $E_{\parallel }$ parallel to $B_{\parallel }$ modifies the effective $B_{\parallel }$ and introduces a magneto-Stark shift in the PL line. This new Stark shift requires $B_{\parallel }\ne 0$ unlike the ordinary Stark shift in perpendicular $E_{\perp }.$

• Received 11 May 1998

DOI:https://doi.org/10.1103/PhysRevB.58.R10187