Stability of soliton lattice phase in the ν=1 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.