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

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.

10 pages, 10 figures

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Cited by in corpus (3)

• Pressure dependence of superconducting critical temperature and upper critical field of 2H-NbS2
• Zero-bias conductance peak in detached flakes of superconducting 2H-TaS${}_2$ probed by scanning tunneling spectroscopy
• Observation of electronic bound states in charge-ordered YBa${}_2$Cu${}_3$O${}_y$