Single-crystal studies and electronic structure investigation of the room-temperature semiconductor NaMnAs

We report synthesis of single crystalline NaMnAs, confirm its antiferromagnetic order and characterise the sample by photoemission spectroscopy. The electronic structure was studied using optical transmittance, x-ray ultraviolet spectroscopy theoretical modeling local density approximation (LDA) extended to LDA+U when Heisenberg model parameters were determined. Optical transmittance measurement have confirmed predictions that NaMnAs is a semiconductor. Also N\'eel temperature closer determined for first time from dependence magnetization, in agreement with our Monte Carlo simulations.