  Inspired by recent theoretical proposal on the interesting piezomagnetism and
C-paired valley polarization in V2Se2O monolayer, we predict a stable
antiferromagnetic Janus monolayer V2SeTeO with altermagnetic configuration
using density functional theory calculations. It exhibits a novel multi-piezo
effect combining piezoelectric, 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 of e31 (0.322*10-10 C m-1). The multi-piezo effect
makes antiferromagnetic Janus monolayer V2SeTeO a tantalizing material for
potential applications in nanoelectronics, optoelectronics, spintronics and
valleytronics.
