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

Synthesis of single-crystalline NaMnAs is reported, and we confirm its high quality by x-ray photoemission spectra. Magnetometry results are consistent with previous findings of antiferromagnetic order. The electronic structure was further studied using optical transmittance and by theoretical modeling using local-density approximation (LDA) extended to LDA + U for the purpose of determining the Heisenberg model parameters. Optical transmittance measurements confirm theoretical predictions that NaMnAs is a semiconductor. The Neel temperature was determined from temperature dependence of susceptibility, in agreement with our Monte Carlo simulations.