  A 1D metallic surface state was created on an anisotropic InSb(001) surface
covered with Bi. Angle-resolved photoelectron spectroscopy (ARPES) showed a 1D
Fermi contour with almost no 2D distortion. Close to the Fermi level ($E_{\rm
F}$), the angle-integrated photoelectron spectra showed power-law scaling with
the binding energy and temperature. The ARPES plot above $E_{\rm F}$ obtained
thanks to thermally broadened Fermi edge at room temperature showed a 1D state
with continuous metallic dispersion across $E_{\rm F}$ and power-law intensity
suppression around $E_{\rm F}$. These results strongly suggest a
Tomonaga-Luttinger liquid on the Bi/InSb(001) surface.
