Acentric magnetic and optical properties of chalcopyrite (CuFeS₂)

Abstract

The absence of spatial inversion symmetry at both local (point group 4) and global (crystal class (4)2m) levels greatly influences the electronic properties of chalcopyrite (CuFeS(2)). The predicted dichroic signals (natural circular, non-reciprocal and magneto-chiral) and resonant, parity-odd Bragg diffraction patterns at space-group forbidden reflections portray the uncommon, acentric symmetry. Despite extensive experimental investigations over several decades, by mineralogists, chemists and physicists, there is no consensus view about the electrical and magnetic properties of chalcopyrite. New spectroscopic and diffraction data, gathered at various temperatures in the vicinity of the copper and iron L(2,3) edges, provide necessary confidence in the magnetic motif used in our analytic simulations of x-ray scattering. With the sample held at 10 and 65 K, our data establish beyond reasonable doubt that there is no valence transition, and ordering of the copper moments as the origin of the low-temperature phase (T(c) ≈ 53 K) is ruled out.

Origin of the Distinct Thermoelectric Transport Properties of Chalcopyrite ABTe2 (A = Cu, Ag; B = Ga, In)

“…In recent years, compounds with the diamond-type structure, such as AgGaTe 2 , [33,34] Cu 2 SnX 3 (X = Se, S), [35][36][37][38] and CuFeS 2 , [39][40][41] have drawn lots of interests in the field of thermoelectrics due to their highly tunable crystal structures and electronic band structures, [42,43] leading to highly tunable physical properties. For example, a maximum ZT value of 0.5 was obtained at 800 K in pristine CuGaTe 2 [44] taking advantage of its excellent electrical properties.…”

The contribution of Diamond Light Source to the study of strongly correlated electron systems and complex magnetic structures

“…Nevertheless, significant insights have been obtained using RSXD [44][45][46], and RSXD is also an area of active interest for Diamond theorists [47][48][49][50]. A good example is provided by the so-called hexaferrites.…”

“…Resonant soft X-ray diffraction (RSXD) is another powerful tool to study multiferroics, although, in the case of transition metal oxides, its applicability is limited to materials where magnetic Bragg peaks are present in the Ewald sphere accessible at the L 2,3 , M 4,5 or O K-edge resonances [43]. Nevertheless, significant insights have been obtained using RSXD [44][45][46], and RSXD is also an area of active interest for Diamond theorists [47][48][49][50]. A good example is provided by the so-called hexaferrites.…”

Layered Cobaltites and Natural Chalcogenides for Thermoelectrics

“…Ternary chalcopyrite-structured chalcogenides, such as CuFeS 2 , have attracted particular attention owing to their unique optical, electrical, magnetic, and thermal properties [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. Studies on chalcopyrite (CuFeS 2 ) have primarily focused on its electronic states [14,15,[29][30][31].…”