3 J un 2 00 7 The Luttinger liquid kink

Spin-charge separation in the one dimensional electron gas should give rise to two peaks in the single hole spectral function. However, unambiguous detection of these two peaks has proven difficult, since the combined effects of interactions, thermal broadening, and finite experimental resolution can suppress the spin peak. Nevertheless, a telltale kink in the dispersion remains, and the systematic temperature dependence of this kink can be used to detect spin-charge separation. Although the two peaks separate at higher binding energies, interactions and temperature strongly suppress the spin peak for repulsive interactions. As a result, the measured peak will disperse with the charge velocity at high energy. This gives rise to a kink in the effective electronic dispersion as derived from measured spectral functions.