[1] Natl Key Lab Sci & Technol Test Phys & Numer Math, Beijing 100076, Peoples R China
[2] Beijing Solar Energy Res, Natl Engn Res Ctr Renewable Energy, Beijing 100012, Peoples R China
[3] Beihang Univ, Ctr Condensed Matter & Mat Phys, Beijing 100191, Peoples R China