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de Oliveira, Raphaela ; Gobato, Yara Galvao ; de Oliveira, Ronei C. ; de Toledo, Jose R. ; Teixeira, Veronica C. ; Malachias, Angelo ; Rabahi, Cesar R. ; Hsu, Chunwei ; de Oliveira, Adilson J. A. ; van der Zant, Herre S. J. ; Barcelos, Ingrid D. ; Cadore, Alisson R.

• Tipo de documento: Artigo Científico
• Fonte: APPLIED CLAY SCIENCE; v. 278, p. 9-pg., 2025-12-15.

Resumo

Biotite crystals are phyllosilicate trioctahedral micas with the general chemical formula K(Mg,Fe)3AlSi3O10(OH)2 that form a solid-solution series with iron-poor phlogopite and iron-rich annite endmembers. With a wide band gap energy and a layered structure with free surface charges, biotite nanosheets can be readily obtained by cleavage methods and used as dielectrics in nanodevice fabrication for the next generation of electronics and energy harvesting. Here, a comprehensive study of biotite samples with different iron concentrations and oxidation states is presented. Structural, optical, magneto-optical, and magnetic characterizations were performed using several experimental techniques, including state-of-the-art synchrotron-based techniques, to correlate the iron chemistry (content and oxidation state) with the macroscopic properties of both minerals. The study reveals a nanoscale-homogeneous Fe distribution via synchrotron X-ray fluorescence mapping, defectmediated optical transitions modulated by Fe3+/Fe2+ ratios, and temperature-dependent magnetic transitions from paramagnetism to competing ferro-/antiferromagnetic interactions. Furthermore, the use of these biotite crystals as substrates for ultrathin heterostructures incorporating monolayer (ML) MoSe2 is explored by magneto photoluminescence at cryogenic temperatures. The results show that the presence of iron impurities in different oxidation states significantly impacts the valley properties for ML-MoSe2. Overall, these findings offer a comprehensive interpretation of the physical properties of bulk biotites in a correlative approach, serving as a robust reference for future studies aiming to explore biotites in their ultrathin form. (AU)

• Processo FAPESP: 24/00989-7 - Centro de Pesquisa em Engenharia Molecular para Materiais Avançados (CEMol)
• Beneficiário: Edson Roberto Leite
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 22/08329-0 - Efeito do padrão de Moiré nas propriedades físicas de heteroestruturas de van der Waals
• Beneficiário: Yara Galvão Gobato
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 22/00419-0 - Heteroestruturas de van der Waals para spintrônica
• Beneficiário: Yara Galvão Gobato
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 23/01313-4 - Propriedades Óticas de Heteroestruturas de van der Waals
• Beneficiário: Yara Galvão Gobato
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 23/11265-7 - Efeito do padrão Moiré nas propriedades físicas de heteroestruturas de van der Waals
• Beneficiário: José Roberto de Toledo
• Modalidade de apoio: Bolsas no Brasil - Programa Fixação de Jovens Doutores
• Processo FAPESP: 21/10293-1 - Síntese e caracterização de nanocompósitos de CeO2/g-C3N4
• Beneficiário: Ronei Cardoso de Oliveira
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado