[1] SN Bose Natl Ctr Basic Sci, Dept Condensed Matter Phys & Mat Sci, Block JD,Sect 3, Kolkata 700106, India
[2] New Alipore Coll, Dept Phys, Kolkata 700053, India
[3] Inst Engn & Management, Sect V, Kolkata 700091, India
[4] CEMS RIKEN, 2-1 Hirosawa, Wako, Saitama 3510198, Japan
[5] Univ Tokyo, Inst Solid State Phys, 5-1-5 Kashiwanoha, Kashiwa, Chiba 2778581, Japan