Dirac mass generation from crystal symmetry breaking on the surfaces of topological crystalline insulators
I. Zeljkovic, Y. Okada, M. Serbyn, R. Sankar, D. Walkup, W. Zhou, J. Liu, G. Chang, Y. Wang, M. Hasan, F. Chou, H. Lin, A. Bansil, L. Fu, V. Madhavan, Nature Materials 14 (2015) 318–324.