Study of the electronic, optical, elastic and infrared properties of trigonal Mg3As2

Trigonal Mg3As2 is a narrow band gap semiconductor, which makes it possible for many technical applications. However, its fundamental properties, such as electronic, optical, elastic and infrared properties, are still not well studied. Here we systematically studied its these properties with the help of first principles calculations. Band structure is obtained and the origins of the bands are revealed by the calculated partial density of states. Its bonding property is analyzed based on the computed electron density difference and Bader charges. Optical dielectric function and the related quantities are derived and discussed. Its mechanical stability and anisotropy is confirmed by the calculated elastic constants. The phonon vibrational modes in its Brillouin zone center are assigned and infrared emission spectrum is simulated. The reason for the disappearance of one infrared peak in the simulated infrared spectrum is revealed. The brittleness, hardness and melting temperature of this crystal are also predicted. The present study can enrich our understanding of trigonal Mg3As2 and facilitate its future applications.