Study of HgBa${}_2$CuO${}_{4+\delta }$ by Angle-Resolved Photoemission Spectroscopy

We present the first angle-resolved photoemission measurement on the single-layer Hg-based cuprate, HgBa${}_2$CuO${}_{4+\delta }$ (Hg1201). A quasi-particle peak in the spectrum and a kink in the band dispersion around the diagonal of the Brillouin zone are observed, whereas no structure is detected near the Brillouin zone boundary. To search for a material-dependent trend among hole-doped cuprates, including Hg1201, we use a tight-binding model to fit their Fermi surfaces. We find a positive correlation between the $T_{c,\mathrm{m}\mathrm{a}\mathrm{x}}$ and $t^{\mathrm{\prime }}\mathrm{/}t$, consistent with theoretical predictions.