Opening an energy gap in an electron double layer system at the integer filling factor in a tilted magnetic field

We employ magnetocapacitance measurements to study the spectrum of a double layer system with gate-voltage-tuned electron density distributions in til ted magnetic fields. For the dissipative state in normal magnetic fields at filling factor nu = 3 and 4, a parallel magnetic field component is found to give rise to the opening of a gap at the Fermi level. We account for the effect in terms of parallel-field-caused orthogonality breaking of the Lan dau wave functions with different quantum numbers for two subbands. (C) 200 0 MAIK "Nauka/Interperiodica".