Spin coherence through light in magnetic semiconductors

• Grant number: 20/15570-0
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2021
• End date: March 31, 2023
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Andre Bohomoletz Henriques
• Grantee: Andre Bohomoletz Henriques
• Host Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Recently, our Research Group discovered that light can induce giant, supergiant and hypergiant spin polarons (SPs) in intrinsic magnetic semiconductors - EuX europium chalcogenides (X = O, S, Se, Te). The magnetic moment of these spin polarons is ten, one hundred and one thousand times greater than the values known so far. The induction of gigantic SPs by a single photon opens a new way to control the magnetic state of matter, using low intensity light. The objective of this work is to understand the process by which the photoexcitation of an SP occurs, and to raise its fundamental static and dynamic characteristics. Many basic questions still remain unanswered, such as: what is the nature of the excited electronic state, which gives rise to an SP? Is it associated with defects, or is it intrinsic? What are the dynamic characteristics of an SP (time of formation and extinction)? What are the ideal conditions to maximize the SPs magnetic moment (temperature, excitation wavelength, external magnetic field)? Is it possible to fully magnetize a material through the formation of SPs? What are the characteristics of the spin waves that are produced when an SP is formed? This work will answer these questions, through experimental investigations of SPs in EuX and other magnetic semiconductors, using the resources of the Magneto-Optics Laboratory of IFUSP, and developing calculations and theoretical models to support the interpretation of exxperimental results. (AU)

Scientific publications

(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)

HENRIQUES, A. B.; VAN KOOTEN, S. C. P.; ABRAMOF, E.; RAPPL, P. H. O.; GALGANO, G. D.. Bound photoinduced giant spin polaron in EuTe. Journal of Applied Physics, v. 131, n. 4, JAN 31 2022. (20/15570-0)

VAN KOOTEN, S. C. P.; SPRINGHOLZ, G.; HENRIQUES, A. B.. Direct optical probing of ultrafast spin dynamics in a magnetic semiconductor. PHYSICAL REVIEW B, v. 105, n. 22, p. 5-pg., 2022-06-29. (20/15570-0)