Scanning tunneling spectroscopy of layers of superconducting 2H-TaSe$_\textbf{2}$: Evidence for a zero bias anomaly in single layers

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

doi:10.1103/physrevb.87.094502

arXiv · 1210.2659

Scanning tunneling spectroscopy of layers of superconducting 2H-TaSe$_\textbf{2}$: Evidence for a zero bias anomaly in single layers

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

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Abstract

We report a characterization of surfaces of the dichalcogenide TaSe$_2$ using scanning tunneling microscopy and spectroscopy (STM/S) at 150 mK. When the top layer has the 2H structure and the layer immediately below the 1T structure, we find a singular spatial dependence of the tunneling conductance below 1 K, 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 $3a_0 \times 3a_0$ charge density wave of 2H-TaSe$_2$. Multilayers of 2H-TaSe$_2$ show a spatially homogeneous superconducting gap with a critical temperature also of 1 K. We discuss possible origins for the peculiar tunneling conductance in single layers.

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J. A. Galvis, P. Rodière, I. Guillamón, M. R. Osorio, J. G. Rodrigo, L. Cario, E. Navarro-Moratalla, E. Coronado, S. Vieira, H. Suderow. 2013-03-04. Scanning tunneling spectroscopy of layers of superconducting 2H-TaSe$_\textbf{2}$: Evidence for a zero bias anomaly in single layers. https://doi.org/10.1103/physrevb.87.094502

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