On the nature of the (de)coupling of the magnetostructural transition in Er$_5$Si$_4$

TL;DR

This paper employs thermodynamic modeling and DFT calculations to understand the decoupling of magnetic and structural transitions in Er$_5$Si$_4$, revealing the stability of phases and electronic entropy behavior during the transition.

Contribution

It introduces a thermodynamic model combined with DFT calculations to explain the decoupling of magnetic and structural transitions in Er$_5$Si$_4$, highlighting phase stability and electronic entropy effects.

Findings

The M structure is the stable phase at low temperatures.

Energy difference at 0 K is -0.262 eV, confirming experimental stability.

Electronic entropy variation is negligible during the transition.

Abstract

In this report, a successful thermodynamical model was employed to understand the structural transition in Er$_5$Si$_4$, able to explain the decoupling of the magnetic and structural transition. This was achieved by the DFT calculations which were used to determine the energy differences at 0 K, using a LSDA+U approximation. It was found that the M structure as the stable phase at low temperatures as verified experimentally with a $\Delta F_0 = -$0.262 eV. Finally, it was achieved a variation of Seebeck coefficient ($\sim$ 6 $\mu$V) at the structural transition which allow to conclude that the electronic entropy variation is negligible in the transition.