[1] Konkuk Univ, Dept Phys, Seoul 05029, South Korea
[2] Inst for Basic Sci Korea, Ctr Correlated Elect Syst, Seoul 08826, South Korea
[3] Seoul Natl Univ, Dept Phys & Astron, Seoul 08826, South Korea
[4] Kookmin Univ, Sch Elect Engn, Seoul 02707, South Korea
[5] Korea Inst Sci & Technol, Adv Anal Ctr, Seoul 02792, South Korea
[6] Korea Univ, Dept Mat Sci & Engn, Seoul 02841, South Korea
[7] Seoul Natl Univ, Dept Mat Sci & Engn, Seoul 08826, South Korea