Optimal orientation of striped states in the quantum Hall system against   external modulations (in 26th ICPS proceedings)
  The physical properties of striped Hall state in the presence of an external unidirectional periodic potential is investigated. The study of searching the optimal orientation of the state is reported for the state at filling factor $\nu=2+1/2$ and for the state at higher Landau levels at $l+1/2$ where $l=3,4,5,6,7,8$. It is predicted that two phases of the orientation, parallel phase and perpendicular phase, exist and a phase transition from one to another phase occurs. 
T. Aoyama, K. Ishikawa, and N. Maeda