Chiral Altermagnetic Magnetoelectrics

Abstract

In this work, we introduce a new class of chiral altermagnetic magnetoelectrics in structurally chiral, nonpolar altermagnetic systems and identify the experimentally well-characterized three-dimensional metal-organic framework K[Co(HCOO)$_3$] as a promising material platform. K[Co(HCOO)$_3$] exhibits chirality-locked \emph{g}-wave altermagnetic spin splitting together with dual-mode switchable electric polarization controlled by N\'eel-vector reorientation and structural chirality. Specifically, N\'eel-vector reorientation generates a finite electric polarization and reverses its sign, whereas chirality switching between left- and right-handed enantiomers produces an additional sign reversal. The associated electronic and optical responses provide effective readout channels for these switchable states. Our results establish chiral altermagnetic magnetoelectrics as a promising route to chirality- and N\'eel-vector-controlled nonvolatile multifunctional spintronics.