1. Institute of Materials Science and Nanotechnology, Bilkent University UNAM, Ankara 06800, Turkey
2. Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
3. Department of Physics, Bilkent University, Ankara 06800, Turkey
4. Korea Research Institute of Standards & Science (KRISS), Daejeon 34113, Republic of Korea