Ground-state and magnetocaloric properties of a coupled spin-electron double-tetrahedral chain (exact study at the half filling)

TL;DR

This paper provides an exact analysis of the ground-state and magnetocaloric properties of a coupled spin-electron double-tetrahedral chain, revealing multiple phases, magnetization plateaus, and effects relevant for magnetic cooling applications.

Contribution

It introduces an exact study of a complex spin-electron chain model, highlighting the interplay of magnetic phases and magnetocaloric effects based on exchange interactions and Landé g-factors.

Findings

Identification of four distinct ground-state phases with different residual entropies.

Observation of one or three magnetization plateaus depending on interaction parameters.

System exhibits both conventional and inverse magnetocaloric effects.

Abstract

Ground-state and magnetocaloric properties of a double-tetrahedral chain, in which nodal lattice sites occupied by the localized Ising spins regularly alternate with triangular clusters half filled with mobile electrons, are exactly investigated by using the transfer-matrix method in combination with the construction of the $N$th tensor power of the discrete Fourier transformation. It is shown that the ground state of the model is formed by two non-chiral phases with the zero residual entropy and two chiral phases with the finite residual entropy $S = Nk_{\rm B}\ln 2$. Depending on the character of the exchange interaction between the localized Ising spins and mobile electrons, one or three magnetization plateaus can be observed in the magnetization process. Their heights basically depend on the values of Land\'e $g$-factors of the Ising spins and mobile electrons. It is also evidenced that the system exhibits both the conventional and inverse magnetocaloric effect depending on values of the applied magnetic field and temperature.