Qiang Gao

Valley splitting is observed between K and −K points in band structures (GGA+U+SOC) of VYNF ₂ . The flat valence bands lead to a robust band gap against strain, where the mechanism behind the flat valence bands is explicated by tight-binding model.

We theoretically introduce a new angular momentum state via the bosonic operator realization of angular momentum operators on a number state, and study its nonclassicality based on the sub-Poissonian distribution, photon number distribution, entanglement entropy and Wigner distribution. The results show that the nonclassicality of the new state for odd q is more stronger than that for even q, and the nonclassicality for any q always enhances first and then weakens with increasing g. Besides, the entanglement always increases with the increase of q for all of g, and finally reaches a maximum when g and h are in certain value ranges and q is large enough.

Based on high-throughput density functional theory calculations, we performed screening for stable magnetic MAB compounds and predicted potential strong magnets for permanent magnet and magnetocaloric applications. The thermodynamical, mechanical, and dynamical stabilities are systematically evaluated, resulting in 21 unreported compounds on the convex hull, and 434 materials being metastable considering convex hull tolerance to be 100 meV per atom. Analysis based on the Hume-Rothery rules revealed that the valence electron concentration and size factor difference are of significant importance in determining the stability, with good correspondence with the local atomic bonding. We found 71 compounds with the absolute value of magneto-crystalline anisotropy energy above 1.0 MJ m⁻³ and 23 compounds with a uniaxial anisotropy greater than 0.4 MJ m⁻³, which are potential gap magnets. Based on the magnetic deformation proxy, 99 compounds were identified as potential materials with interesting magnetocaloric performance.

Based on density functional theory calculations, we investigated two-dimensional in-plane ordered MXenes (i-MXenes), focusing particularly on their magnetic properties.