Altermagnets have recently attracted significant attention, yet their coupling to other ferroic orders remains to be explored. In this work, we investigate the interplay of altermagnetism and ferroelectricity in pentagonal $\mathrm{Mn}{X}_2$ ($X=\mathrm{S}$, Se) monolayers using density functional theory (DFT) calculations and symmetry analysis. We show that both materials host robust $g$-wave altermagnetism with a room-temperature Néel transition ($T_N$), stabilized by strong exchange interactions mediated through ligand dimers. At the same time, pronounced Mn-$d$ and S/Se-$p$ hybridization generates type II ferroelectricity, which locks the Néel vector to the out-of-plane polarization, thus enabling electrical stabilization of the magnetic order under finite temperature. Furthermore, we show that compressive strain enhances magnetic couplings, and propose Janus $\mathrm{MnSSe}$ as a system with enhanced altermagnetism and ferroelectricity. These findings unveil how altermagnetism and ferroelectricity coexist in pentagonal $\mathrm{Mn}{X}_2$ ($X=\mathrm{S}$, Se) monolayers at a microscopic level, providing interesting perspectives for designing multifunctional two-dimensional materials in spintronic applications.

Close

PrevNext

View figure in article

• Altermagnetism
• Electronic structure of atoms & molecules
• Ferroelectricity
• Magnetoelectric effect
• Multiferroics
• Density functional theory