摘要
In this paper, based on symmetry analysis and the first-principles electronic structure calculations, we demonstrate that the vally Hall effect without time-reversal symmetry can be realized in two-dimensional altermagnetic materials Fe2WSe4 and Fe2WS4. Due to crystal symmetry required, the vally Hall effect without time-reversal symmetry is called crystal vally Hall effect. In addition, under uniaxial strain, both monolayer Fe2WSe4 and Fe2WS4 can realize piezomagnetic effect.