| Recent theory shows that the spectral function A(k,w) of a non-Fermi liquid should display a so-called ¡Luttinger surface¢, the equivalent of a Fermi surface for a non-Fermi liquid. TTF-TCNQ (tetrathiafulvalene-tetracyanoquinodimethane) has been extensively studied for its structural and transport properties and serves as a classic example of a quasi-one-dimensional(1D) correlated metal with charge-density waves(CDW). The strong electron-electron correlations result in making the system a very suitable example of a quasi-1D metal exhibiting spin-charge separated branched dispersions, consistent with the one-dimensional Hubbard model. This study investigates the existence of the "Luttinger surface" of TTF-TCNQ, and its temperature dependence using angle-resolved photoemission spectroscopy(ARPES). TTF-TCNQ exhibits peaks in MDC's which define and map its Luttinger surface. The Luttinger surface topology, obtained from momentum distribution curves, changes from quasi-2D (dimensional) to quasi-1D with temperature. The high temperature quasi-2D surface exhibits 4kF charge-density-wave (CDW) superstructure in the TCNQ derived holon band, in the absence of 2kF order. Decreasing temperature results in quasi-1D nested 2kF CDW order in the TCNQ spinon band and in the TTF surface. The results show the link in momentum space between charge order and spin-charge separation in a Luttinger liquid. |
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