Stability of soliton lattice phase in the image bilayer quantum Hall state under tilted magnetic fields

The bilayer quantum Hall (QH) state at the filling factor ν=1 shows various fascinating quantum phenomena due to the layer degree of freedom called ‘pseudospin’. We report an experimental evidence of the soliton lattice (SL) phase, which is a domain structure of pseudospin, by the appearance of a local maximum of magnetoresistance near the ν=1 QH state. We investigate the stability of the SL phase by changing B∥ and the total electron density nT. Detailed magnetotransport measurements under tilted magnetic fields were carried out to obtain a B∥–nT plane phase diagram containing the C, IC and SL phases. We found the SL phase is only stable at low nT region. Namely, the C–SL–IC phase transition occurs only at low nT region as B∥ increases. On the contrary, the C–IC phase transition directly occurs without passing through the SL phase at high nT region.