Coexistence of High-T_c Ferromagnetism and n-Type Electrical Conductivity in FeBi₂Se₄

Abstract

The discovery of n-type ferromagnetic semiconductors (n-FMSs) exhibiting high electrical conductivity and Curie temperature (Tc) above 300 K would dramatically improve semiconductor spintronics and pave the way for the fabrication of spin-based semiconducting devices. However, the realization of high-Tc n-FMSs and p-FMSs in conventional high-symmetry semiconductors has proven extremely difficult due to the strongly coupled and interacting magnetic and semiconducting sublattices. Here we show that decoupling the two functional sublattices in the low-symmetry semiconductor FeBi2Se4 enables unprecedented coexistence of high n-type electrical conduction and ferromagnetism with Tc ≈ 450 K. The structure of FeBi2Se4 consists of well-ordered magnetic sublattices built of [FenSe4n+2]∞ single-chain edge-sharing octahedra, coherently embedded within the three-dimensional Bi-rich semiconducting framework. Magnetotransport data reveal a negative magnetoresistance, indicating spin-polarization of itinerant conducting electrons. These findings demonstrate that decoupling magnetic and semiconducting sublattices allows access to high-Tc n- and p-FMSs as well as helps unveil the mechanism of carrier-mediated ferromagnetism in spintronic materials.

PHASE DIAGRAMS OF THE FeGa2S4- FeIn2S4 AND FeS- FeGaInS4 SYSTEMS

“…Of special interest are valuable functional materials with complex metal chalcogenidesand-based phases characterized by thermoelectric, photoelectric, optical, magnetic, topological insulator and other properties [1][2][3][4][5][6] and AB 2 X 4 magnetic compounds (A-Mn, Fe, Co, Ni, B-p 1 -p 3 elements, X-chalcogen). They are promising materials for the production of wide-gap converters of optical radiations, light modulators, photo-detectors, as well as spintronic and other magnetic-fieldcontrollable functional devices [7][8][9][10][11].…”

Synthesis, Crystal, and Electronic Structure of Ba3Sb2Q7 (Q = S, Se)

“…[19][20][21][22] Centrosymmetric antimony chalcogenides also exhibit prospective thermoelectric [9,10,[23][24][25] and magnetic properties. [26,27] Despite the large number of known ternary, quaternary, and polyternary antimony chalcogenides, only a few compounds in the Ba-Sb-Q (Q = S, Se) systems have been reported: Ba 8 Sb 6 S 17 , [28] BaSb 2 S 4 , [29] Ba 3 Sb 4.67 S 10 , [30] Ba 4 Sb 4 Se 11 , [31] and BaSb 2 Se 4 . [32] We performed a systematic search for new barium antimony chalcogenides and found two new isostructural compounds, Ba 3 Sb 2 S 7 and Ba 3 Sb 2 Se 7 .…”

Rejecting the death of passwords: Advice for the future

“…One possibility is spintronic semiconductors, which exploit electrons' rotational energy rather than their charge to represent bits. While this technology has been in development for more than 15 years, there are still challenges that need to be overcome before it can reach the production stage [17].…”