1. Department of Theoretical Physics,
Faculty of Physics, Vilnius University,
Sauletekio Avenue 9, build. 3, LT-10222 Vilnius, Lithuania
2. Center for Physical Sciences
and Technology, Institute of Physics, Savanoriu Avenue 231, LT-02300
Vilnius, Lithuania
3. State
Key Laboratory of Supramolecular
Structure and Materials, Jilin University, 2699 Qianjin Street, Changchun 130012, PR China