Fermi-liquid line shapes measured by angle-resolved photoemission spectroscopy on $\mathrm{1-T -TiTe_2}$

We have performed high-resolution angle-resolved photoemission spectroscopy (ARPES) on the layered compound 1-T-TiTe$_2$, whose low-energy properties are those of a normal metal, and analyzed the experimental line shapes in terms of the Fermi-liquid self-energy. We find excellent agreement between the measured and theoretical spectral weight distribution, while line profiles expected for other theoretical models such as the marginal Fermi liquid clearly fail to reproduce the experimental spectra. This demonstrates that ARPES line shapes are able to reflect the nature of an interacting electron system