The distribution of the electron density and spin density in the interplanar areas CuFeS2by NMR63,65Cu in a local field

Aleksandr Pogoreltsev,Valery Galiakhmetov,Vadim Matukhin,Ekaterina Shmidt,Yaroslav Shaikhutdinov,V.A Golenishchev-Kutuzov

doi:10.1051/e3sconf/202128801050

Aleksandr Pogoreltsev, Valery Galiakhmetov + Show 4 more

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https://doi.org/10.1051/e3sconf/202128801050

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Abstract

Chalcopyrite CuFeS2is a known semiconductor mineral with a wide range of unique physical and chemical properties. These materials can be used as elements of solar batteries, coherent and incoherent sources of polarized radiation, in photovoltaic, thermoelectric and spintronic devices. Despite the relatively large number of studies on CuFeS2, many questions about its magnetic and electronic properties, are still outstanding. In this paper we were carried out studies of the distribution of the electron density and spin density in the nuclei of iron and copper in the semiconductor mineral CuFeS2. Special attention was devoted to interrelation of electronic and spin subsystems of the compound. The results of studies of the compound obtained in NMR63,65Cu local field at low temperatures were used to perform the corresponding analysis. The cluster approach was used. The biggest cluster had Cu9Fe10S28-4formula. Calculations were carried out in the framework of restricted self-consistent Hartree - Fock with open shells (SCF-LCAO-ROHF), MINI basis. The calculations were made with the “foundation” on the quadrupole parameters (quadrupole νQ frequency and the asymmetry parameter of the electric field gradient tensor η), obtained from the experiment. Study of electron density maps were performed for the regions containing chains of Fe-S-Cu and S-Fe-S for the different layers of metals and sulfur atoms. It is shown that the nature of the connection of iron atoms belonging to neighboring layers with sulfur atoms of the intermediate layer is different, which is reflected on the electron density distribution.

Highlights

Chalcopyrite CuFeS2 belongs to the class of magnetic semiconductors that allow, by varying their chemical composition and structure, to obtain materials with a wide range of physical characteristics, such as band gap, type of conductivity, specific electrical conductivity, etc
Are the lines connecting the atoms of the communication line, the blue dots on the lines of communication – a critical point of (3,1), blue line passing through the points (3,1) – base line, which separates the basins of the atoms
The Fe14-S43 bond is characterized by a closed behavior of electron density lines – it is localized in the region of its core, respectively, the nature of this bond is close to the ionic one

Summary

Introduction

Chalcopyrite CuFeS2 belongs to the class of magnetic semiconductors that allow, by varying their chemical composition and structure, to obtain materials with a wide range of physical characteristics, such as band gap, type of conductivity, specific electrical conductivity, etc. These materials can be used as solar cells, coherent and incoherent sources of polarized radiation, in photovoltaic, thermoelectric and spintronic devices [17]. With the successive alternation of copper and iron atoms, the spins of iron atoms are located parallel along the c axis, and in neighboring layers — antiparallel, which leads to an antiferromagnetic ordering of the CuFeS2 crystal lattice with a Neel temperature of 823 K[14, 15]. This compound has a wide band gap distribution from 3.5 to

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