Spin-density wave versus superconducting fluctuations for quasi-one-dimensional electrons in two chains of Tomonaga-Luttinger liquids

TL;DR

This paper investigates the competition between spin-density wave and superconducting fluctuations in coupled Tomonaga-Luttinger liquids, revealing phase transitions and crossover behaviors relevant for quasi-one-dimensional organic conductors.

Contribution

It applies the renormalization-group method to analyze phase competition in two coupled chains of Tomonaga-Luttinger liquids with interactions and hopping.

Findings

Identification of three distinct fluctuation regimes at low temperatures.

Crossover from SDW to SC state in a specific fluctuation regime.

Insights into the phase diagram of quasi-one-dimensional organic conductors.

Abstract

We study possible states at low temperatures by applying the renormalization-group method to two chains of Tomonaga-Luttinger liquids with both repulsive intrachain interactions and interchain hopping. As the energy decreases below the hopping energy, three distinct regions I, III, and II appear successively depending on properties of fluctuations. The crossover from the spin-density wave (SDW) state to superconducting (SC) state takes place in region III where there are the excitation gaps of transverse charge and spin fluctuations. The competition between SDW and SC states in region III is crucial to understanding the phase diagram in the quasi-one-dimensional organic conductors.