Observation of novel gapped phases in potassium doped single layer p-terphenyl on Au (111)

M. Q. Ren; W. Chen; Q. Liu; C. Chen; Y. J. Qiao; Y. J. Chen; G. Zhou; T. Zhang; Y. J. Yan; D. L. Feng

doi:10.1103/physrevb.99.045417

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arXiv · 1705.09901

Observation of novel gapped phases in potassium doped single layer p-terphenyl on Au (111)

M. Q. Ren·W. Chen·Q. Liu·C. Chen·Y. J. Qiao·Y. J. Chen·G. Zhou·T. Zhang·Y. J. Yan·D. L. Feng

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Abstract

Recently, superconductivity in potassium (K) doped p-terphenyl (C18H14) has been suggested by the possible observation of the Meissner effect and subsequent photoemission spectroscopy measurements, but the detailed lattice structure and more-direct evidence are still lacking. Here we report a low temperature scanning tunneling microscopy/spectroscopy (STM/STS) study on K-doped single layer p-terphenyl films grown on Au (111). We observe several ordered phases with different morphologies and electronic behaviors, in two of which a sharp and symmetric low-energy gap of about 11 meV opens below 50 K. In particular, the gap shows no obvious response to a magnetic field up to 11 Tesla, which would caution against superconductivity as an interpretation in previous reports of K-doped p-terphenyl materials. Such gapped phases are rarely (if ever) observed in single layer hydrocarbon molecular crystals. Our work also paves the way for fabricating doped two-dimensional (2D) hydrocarbon materials, which will provide a platform to search for novel emergent phenomena.

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M. Q. Ren, W. Chen, Q. Liu, C. Chen, Y. J. Qiao, Y. J. Chen, G. Zhou, T. Zhang, Y. J. Yan, D. L. Feng. 2017-05-28. Observation of novel gapped phases in potassium doped single layer p-terphenyl on Au (111). https://doi.org/10.1103/physrevb.99.045417

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