1210.2659 (J. A. Galvis et al.)

Flat band in superconducting layers of 2H-TaSe2    [PDF]

J. A. Galvis, P. Rodière, I. Guillamón, M. R. Osorio, J. G. Rodrigo, L. Cario, E. Navarro-Moratalla, E. Coronado, S. Vieira, H. Suderow

We report scanning tunneling spectroscopy measurements at 150 mK in single layer crystals of 2H-TaSe2. We find a singular spatial dependence of the tunneling conductance, changing from a zero bias peak on top of Se atoms to a gap in between Se atoms. The zero bias peak is additionally modulated by the commensurate 3a0 X 3a0 charge density wave of 2H-TaSe2. Multilayers of 2H-TaSe2 show, by contrast, a homogeneous superconducting gap with a critical temperature of about 1 K. The zero bias peak in single layers of 2H-TaSe2 evidences a zero energy bound state. We discuss possible origins for such a peculiar electronic spectrum, which seems to be characteristic of small superconducting single layers of 2H-TaSe2.

View original: http://arxiv.org/abs/1210.2659