On the ground-state degeneracy and entropy in a double-tetrahedral chain formed by the localized Ising spins and mobile electrons

TL;DR

This paper provides an exact analysis of the ground-state degeneracy and entropy in a hybrid double-tetrahedral chain with localized Ising spins and mobile electrons, revealing complex phase behavior and thermodynamic signatures.

Contribution

It introduces an exact solution for the ground-state properties of a hybrid double-tetrahedral chain, highlighting diverse degeneracy and phase transitions not previously characterized.

Findings

Multiple ground-state phases with varying degeneracy levels.

Presence of multiple-peak structures in thermodynamic quantities.

Distinct temperature dependencies of specific heat with Schottky maxima.

Abstract

Ground-state properties of a hybrid double-tetrahedral chain, in which the localized Ising spins regularly alternate with triangular plaquettes occupied by a variable number of mobile electrons, are exactly investigated. We demonstrate that the zero-temperature phase diagram of the model involves several non-degenerate, two-fold degenerate and macroscopically degenerate chiral phases. Low-temperature dependencies of the entropy and specific heat are also examined in order to gain a deeper insight into the degeneracy of individual ground-state phases and phase transitions. It is shown that a diversity of the ground-state degeneracy manifests itself in multiple-peak structures of both thermodynamic quantities. A remarkable temperature dependencies of the specific heat with two and three Schottky-type maxima are discussed in detail.