Many-body effects on Valley qubits and on the magneto-optical properties of transition metal dichalcogenide monolayers

• Grant number: 17/23668-8
• Support Opportunities: Scholarships in Brazil - Post-Doctorate
• Effective date (Start): March 01, 2018
• Effective date (End): September 23, 2019
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Victor Lopez Richard
• Grantee: Helena de Souza Bragança Rocha
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 14/19142-2 - Characterization and processing of semiconductor nanostructures and application as devices, AP.TEM

Abstract

The fabrication and characterization of graphene, in 2004, have opened new paths to the realization of a truly two-dimensional gas, with great perspectives to study both fundamental and applied physics related to quantum Hall effect, fractional quantum Hall effect, quantum anomalous Hall effect, quantum spin Hall effect, topological insulators, etc. Due to the low dimensionality and the special crystalline structure, graphene displays very interesting physical properties, such as ultrahigh electron mobility, linear dispersion around Dirac points K and K' and large spin coherent length. On the other hand, monolayers of Transition Metal Dichalcogenides (TMDs), such as MoS2, MoSe2, WS2 and WSe2, were discovered recently. These materials display properties complementary to those of graphene: an asymmetry over the inversion of crystalline structure, large band gap, strong spin-orbit coupling and large Coulomb interaction. Furthermore, these new two-dimensional materials can be organized in three-dimensional heterostructures which do not exist in nature and have controlled properties, opening a totally new chapter in the study of Condensed Mater Physics. Despite great advances in the synthesis of these materials, the fundamental understanding of the origin of important properties is still not well developed. The proposal of microscopic theories can support the interpretation of experimental results and also lead to the prediction of new properties. The goal of this project is to assist the development of new devices which use many-body properties and the spin and valley degree of freedom of the TMDs monolayers. The project will allow the integration of a researcher who has recently finished the PhD in strongly-correlated systems to the research group of Semiconductor Nanostructures of UFSCar, which has large experience on the theoretical study of electronic and optical properties of nanoscopic systems and of the application of such materials to technological devices. The group has also collaboration with experimentalists, allowing an interplay between theory and experiment. (AU)

Scientific publications

(5)

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

NARANJO, A.; BRAGANCA, H.; JACOBSEN, G. M.; DE MORAIS, R. R. O.; QUIVY, A. A.; MARQUES, G. E.; LOPEZ-RICHARD, V; TEODORO, M. D.. Magnetic and power tuning of spin-asymmetric multiple excitons in a GaAs quantum well. PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, v. 129, MAY 2021. (18/01914-0, 17/23668-8, 13/18719-1, 14/19142-2)

QU, FANYAO; BRAGANCA, HELENA; VASCONCELOS, RAILSON; LIU, FUJUN; XIE, S-J; ZENG, HAO. Controlling valley splitting and polarization of dark- and bi-excitons in monolayerWS(2) by a tilted magnetic field. 2D MATERIALS, v. 6, n. 4, OCT 2019. (17/23668-8)

BRAGANCA, HELENA; RICHE, FLAVIO; QU, FANYAO; LOPEZ-RICHARD, VICTOR; MARQUES, GILMER EUGENIO. Dark-exciton valley dynamics in transition metal dichalcogenide alloy monolayers. SCIENTIFIC REPORTS, v. 9, MAR 14 2019. (17/23668-8)

RICHE, FLAVIO; BRAGANCA, HELENA; QU, FANYAO; LOPEZ-RICHARD, VICTOR; XIE, S. J.; DIAS, A. C.; MARQUES, GILMER EUGENIO. Robust room temperature emissions of trion in darkish WSe(2)monolayers: effects of dark neutral and charged excitonic states. JOURNAL OF PHYSICS-CONDENSED MATTER, v. 32, n. 36, AUG 26 2020. (17/23668-8)

BRAGANCA, HELENA; VASCONCELOS, RAILSON; FU, JIYONG; D'AZEVEDO, RENNAN PINHEIRO; DA COSTA, DIEGO RABELO; FONSECA, A. L. A.; QU, FANYAO. Magnetic brightening, large valley Zeeman splitting, and dynamics of long-lived A and B dark excitonic states in monolayer WS2. Physical Review B, v. 100, n. 11, SEP 5 2019. (17/23668-8)