Charge density wave instability in a parabolic well in perpendicular magnetic field

We report magnetotransport measurements of a wide parabolic quantum well with quasi-two-dimensional holes in a tilted magnetic field. We find that in a perpendicular magnetic field the magnetoresistance minima at filling factor ν=1 are missed. This effect is attributed to the formation of the charge density wave (CDW) state proposed theoretically by Brey for quantum Hall system with several subbands (Phys. Rev. B 44 (1991) 3772). In the tilted magnetic field CDW state is destroyed and quantum Hall effect is recovered.