Observation of Dirac-like energy band and unusual spectral line shape in quasi-one-dimensional superconductor Tl 2 Mo 6 Se 6

摘要: We have performed high-resolution angle-resolved photoemission spectroscopy of the quasi-one-dimensional (1D) topological superconductor candidate ${\mathrm{Tl}}_{2}{\mathrm{Mo}}_{6}{\mathrm{Se}}_{6}$ consisting weakly coupled ${\mathrm{Mo}}_{3}{\mathrm{Se}}_{3}$ chains. found a quasi-1D Fermi surface arising from Dirac-like energy band, which is associated with nonsymmorphic screw symmetry chains and predicted to trigger superconductivity. observed significant spectral-weight reduction over wide range, together tiny Fermi-edge structure exhibits signature superconducting-gap opening below superconducting-transition temperature. The band its very small density states point an unconventional nature superconductivity in ${\mathrm{Tl}}_{2}{\mathrm{Mo}}_{6}{\mathrm{Se}}_{6}$.