RbCeX2 Crystal (X = S, Se, Te): Pressure-Induced Spin-Selective Gapless Transition and Response Properties

• Published in: Journal of alloys and compounds 2022-03, Vol.898, p.162760, Article 162760
• Main Authors: Azzouz, Lahcene, Halit, Mohamed, Denawi, Hassan, Charifi, Zoulikha, Baaziz, Hakim, Rérat, Michel, Matta, Chérif F.
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Congeners; Crystal structure; Crystals; crystals under pressure; Curie temperature; Density functional theory; Ferromagnetic phases; Ferromagnetism; infrared and Raman spectra; Magnetic properties; Magnetic semiconductors; or physical chemistry; periodic DFT calculations; spin-gapless semiconductors; Tellurium; Theoretical and
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2021.162760

•A new pressure-switchable magnetic semiconductor (RbCeX2, X = Te) is proposed and contrasted with two other related compounds X = S, Se.•Spin-polarized calculations establish a ferromagnetic configuration for RbCeX2, where X = S, Se, Te.•RbCeTe2 is a semiconductor with two spin band gap channels that respond differently to moderate hydrostatic pressures (of 5, 10 GPa).•Moderate pressures induce a change in the magnetic semiconductor behavior of only the Te compound to a spin-gapless semiconductor, but this effect is not observed for neither the S nor the Se congeners.•Physical properties of RbCeTe2 suggest its potential for photoresponse applications. [Display omitted] Crystal structures, electronic, and magnetic properties of RbCeX2 (X = S, Se, Te) crystals are investigated using periodic density functional theory (DFT) calculations under hydrostatic pressures up to 10 GPa. The ferromagnetic phase is slightly more stable than the anti-ferromagnetic one for all compounds and pressures. A pressure-induced transition from a magnetic semiconductor (MS) to a spin gapless semiconductor (SGS) is observed only in the case of the X = Te compound. In absence of imposed pressure, the X = Te exhibits a direct α-spin gap of 0.46 eV while its β-gap is 2.30 eV. A pressure of 10 GPa completely suppresses the α-spin gap of RbCeTe2 and reduces it β-gap to 1.63 eV. This pressure-induced elimination of only one spin gaps is exclusive to the X = Te compound. This property distinguishes the Te compound from its two congeners. The pressure-response characteristics of RbCeTe2 renders this compound a potential pressure-induced MS → SGS switching material.