Magnetic orders and electronic behaviours of new chalcogenides Cu₃MnCh₄ (Ch = S, Se and Te): An ab initio study

ABSTRACT

The ternary copper-based chalcogenides Cu₃MnCh₄ (Ch = S, Se and Te), which have simple cubic (SC) crystal structure and conform to $P\overline{4}3m$ space group with 215 space number, have been investigated by spin-polarised Generalised Gradient Approximation (GGA) in the framework of Density Functional Theory (DFT). First, all systems have been considered in ferromagnetic (FM) and three different type antiferromagnetic (AFM) orders which are A-type (A-AFM), G-type (G-AFM) and C-type (C-AFM) to investigate most stable magnetic phase for each system. The energetically favoured magnetic phase is A-type AFM for Cu₃MnS₄ and Cu₃MnSe₄ compounds, while Cu₃MnTe₄ compound has FM ground state. The electronic band structures of these systems have been investigated, after the well-optimised structural parameters in their stable magnetic phase have been obtained. The calculated spin-polarised electronic band structure of FM Cu₃MnTe₄ compound exhibits half-metallic behaviour with a band gap in minority spin channel (E_g = 0.99 eV) while metallic band structure is observed for majority spin. The calculated electronic band structures in A-type AFM phase for Cu₃MnS₄ and Cu₃MnSe₄ systems show that Cu₃MnS₄ compound has semiconducting behaviour with a small band gap (E_g = 0.21 eV) whereas Cu₃MnSe₄ compound has metallic character. The calculated negative formation enthalpies indicate the thermodynamic stability and structural synthesisability of these compounds.

KEYWORDS:

• Half-metallic
• semiconductor
• metallic
• electronic structure of bulk materials
• antiferromagnet
• ferromagnet
• mechanical properties of solids
• density functional theory
• chalcogenides

Acknowledgments

This research was supported in part by TÜBİTAK (The Scientific & Technological Research Council of Turkey) through TR-Grid e-Infrastructure Project, part of the calculations has been carried out at ULAKBİM Computer Center.

Disclosure statement

No potential conflict of interest was reported by the author.