Temperature dependent Luttinger surfaces

TL;DR

This study investigates how the Luttinger surface topology in an organic metal changes with temperature, revealing a transition from quasi-2D to quasi-1D structures and linking charge order with spin-charge separation.

Contribution

It provides the first temperature-dependent analysis of Luttinger surfaces in TTF-TCNQ, demonstrating a dimensional crossover and its relation to charge density waves and spin-charge separation.

Findings

Luttinger surface topology shifts from quasi-2D to quasi-1D with decreasing temperature.

High-temperature surface shows 4$k_F$ charge-density-wave superstructure without 2$k_F$ order.

Lower temperatures induce quasi-1D nested 2$k_F$ CDW order in spinon and TTF bands.

Abstract

The Luttinger surface of an organic metal (TTF-TCNQ), possessing charge order and spin-charge separation, is investigated using temperature dependent angle-resolved photoemission spectroscopy. 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 4$k_F$ charge-density-wave (CDW) superstructure in the TCNQ derived holon band, in the absence of 2$k_F$ order. Decreasing temperature results in quasi-1D nested 2$k_F$ CDW order in the TCNQ spinon band and in the TTF surface. The results establish the link in momentum-space between charge order and spin-charge separation in a Luttinger liquid.