Oxidation and magnetic states of chalcopyrite CuFeS2: A first principles calculation

Abstract

The ground state band structure, magnetic moments, charges and population numbers of electronic shells of Cu and Fe atoms have been calculated for chalcopyrite CuFeS 2 using density functional theory. The comparison between our calculation results and experimental data (X-ray photoemission, X-ray absorption and neutron diffraction spectroscopy) has been made. Our calculations predict a formal oxidation state for chalcopyrite as Cu 1+ Fe 3+ S 2 2-. However, the assignment of formal valence state to transition metal atoms appears to be oversimplified. It is anticipated that the valence state can be confirmed experimentally by nuclear magnetic and nuclear quadrupole resonance and Mössbauer spectroscopy methods.

Electrical and magnetic properties of FeS2 and CuFeS2 nanoplates

“…12,13 While, the band structure of CuFeS 2 calculated (Fig. 5d) exhibited conductivity properties, 20 which has been explained by assuming that CuFeS 2 was a degenerate semiconductor. 21 The electrical properties of FeS 2 and CuFeS 2 nanoplates fabricated by "gold-wire mask moving" method 22,23 were measured from 300 K to 10 K. The conductivities of FeS 2 and CuFeS 2 were 2.21 s cm À1 and 9.92 Â 10 2 s cm À1 at room temperature.…”

Comparison study of crystal and electronic structures for chalcopyrite (CuFeS2) and pyrite (FeS2)

“…Zhou et al (2015) gave a band gap of 0.55 eV by using GGA+U with a U value of 3 eV for the 3d state of Fe, whereas Martínez-Casado et al (2016) predicted a value of 1.82 eV by the DFT-B3LYP method. In addition, theoretical calculations often give conductive properties (Edelbro et al, 2003;Klekovkina et al, 2014). This is inconsistent with the experimental results that chalcopyrite has semiconducting properties Douglas, 1954, Austin et al, 1956).…”

“…Many experimental and theoretical studies have been reported on the magnetic and electronic properties of chalcopyrite and pyrite (Ennaoui et al, 1993;Conejeros et al, 2015;Teranishi, 1961;Lazewski et al, 2004;Zhou et al, 2015;Lyubutin et al, 2013;Klekovkina et al, 2014;Kradinova et al, 1999). Pyrite is suggested as a semiconductor with a narrow band gap, but chalcopyrite is suggested as a conductor or semiconductor.…”

Sustainable rehabilitation of mining waste and acid mine drainage using geochemistry, mine type, mineralogy, texture, ore extraction and climate knowledge

“…The electrochemical oxidation of chalcopyrite generated insoluble sulfur species (e.g., S , S n 2À , etc.) forming a passivation layer on the mineral surface and decreasing the dissolution kinetics (Xian et al, 2012;Klekovkina et al, 2014). But they facilitated attachment of Fe and S-oxidizing microorganisms on mineral surface (Lara et al, 2013) and prevented such effect through biooxidation of reduced sulfur species (Anjum et al, 2012).…”