Multipiezo Effect in Altermagnetic V₂SeTeO Monolayer

Strain engineering has been used as an efficient method to modulate various properties of quantum materials and electronic devices. One may establish piezo effects based on a disciplined response to the strain in multifunctional nanosystems. Inspired by a recent theoretical proposal on the interesting piezomagnetism and C-paired valley polarization in the V₂Se₂O monolayer, we predict a stable altermagnetic Janus monolayer V₂SeTeO using density functional theory calculations. It exhibits a novel "multipiezo" effect combining piezoelectricity, piezovalley, and piezomagnetism. Most interestingly, the valley polarization and the net magnetization under strain in V₂SeTeO exceed these in V₂Se₂O, along with the additional large piezoelectric coefficient. The "multipiezo" effect makes Janus monolayer V₂SeTeO as a tantalizing material for potential applications in nanoelectronics, optoelectronics, spintronics, and valleytronics.