Massive Dirac fermion on the surface of a magnetically doped topological insulator. (Science (New York, N.Y.), 2010)

(untitled) - Chen, Y; Chu, J; Analytis, J; Liu, Z; Igarashi, K; Kuo, H; Qi, X; Mo, S; Moore, R; Lu, D; Hashimoto, M; Sasagawa, T; et al.