All-inorganic cesium lead halide perovskite nanocrystals have been widely investigated as promising materials for light and display. The primary challenge for their practical application is development of highly efficient and...

We study the strain tuning of magnetism in Mn doped MoS2 monolayer system. With the increase of the tensile strain, the magnetic ground state changes from a state with total magnetic moment Mtot =1.0 B to another state with Mtot =3.0 B for single doping in a 4 × 4 supercell. Physical mechanism is elucidated from the effects of the local bonding and geometry symmetries on orbital hybridization. In addition, we find the ferromagnetic coupling is favored for small distances between Mn atoms corresponding to the uniform doping concentration of 25%. More importantly, the ferromagnetic state is highly stable and robust to tensile strains. Therefore, diluted magnetic semiconductors can be obtained and the strain engineering should be a very promising approach to tune the magnetic moments.

The iridate Na2IrO3 was proposed to be a realization of the Kitaev model with a quantum spin liquid ground state. Experiments have now established that this material hosts a zigzag antiferromagnetic order. However, the previous assignment of the ordered moment direction to the a axis is controversial. We examine the magnetic moment direction of Na2IrO3 using the local spin density approximation plus spin orbit coupling+U calculations. Our calculations reveal that the total energy is minimized when the zigzag-ordered moments are aligned along g≈a+c direction. The dependence of the total energy on moment directions can be explained by adding anisotropic interactions to the nearest-neighbor Kitaev-Heisenberg model, on which the spin-wave spectrum is also calculated. The revision of ordered moments is very important to understanding and achieving possible exotic electronic phases in this compound.