The study of the electronic structure of RuS2

Abstract In this study, through theoretical and experimental analyses, we demonstrated that unlike most semiconductors, Ru S 2 has different indirect bandgaps, which makes it a distinct energy conversion and storage device. In our experimental work, we used the chemical vapor transport and solvent evaporation methods. We obtained Ru S 2 at a low temperature of 800 °C with different stoichiometric shifts of sulfur, such as Ru S 2.00 , Ru S 1.96 , and Ru S 1.90 . Moreover, we studied the correlation between the band structure of RuS2 calculated using the linear muffin-tin orbitals-atomic sphere approximation (LMTO-ASA) method and the growth parameters for each sample. We obtained some noteworthy values of indirect bandgap, such as, 1.84 , 1.72 , 1.42 , a n d 1.25 e V , and direct transition, such as, 2.04 , 1.93 , 1.77 , a n d 1.49 e V . The bandgap values obtained by LMTO-ASA are. 1.80727 , 1.69614 , 1.46743 , a n d 1.23522 e V . We obtained indirect bandgaps and a direct transition at the gamma point; their values are 2.04 , 1.94 , 1.77 , and 1.49 e V . We found that Ru S 2 has valence and conduction bands. The gap energy evaluated by LMTO-ASA was close to the value of that obtained through experimental measurements. We showed that band energy is insensitive to the lattice constant, a . Bandgaps depend on the method of preparation because they change with the temperature and structure ( ν ) . Similar results were obtained for the effective mass. We found two phonons at X and M points, as well as the probability of the existence of two indirect transitions to the bandgap. To the best of our knowledge, this is the first study to confirm that the position of sulfur and S–S distance significantly affect the bandgap.