Surface nanowire hosting a Tomonaga-Luttinger liquid with two-component spectral feature implying spin-charge separation

One-dimensional metallic surface state is created in atomic Bi-nanowires prepared on InSb(001) semiconductor substrate. Angle-resolved photoelectron spectroscopy (ARPES) reveals its spectral feature down to 8 K, showing the power-law scaling with binding energies around the Fermi level (EF) as well as the temperature dependence of the photoelectron intensities. ARPES shows that the surface state band consists of two separate features dispersing with different Fermi velocity but touching each other at EF, suggesting a spin-charge separation. These results strongly suggest that a Tomonaga-Luttinger liquid is realized in the Bi-nanowire system on InSb(001). PACS numbers: 71.20.-b, 73.20.At, 79.60.-i, 71.10.Pm