Programme

O.17 -- Oral, VCTP-48

Date: Thursday, 3 August 2023

Time: 16:40 - 17:05

Magnetic properties in diluted magnetic semiconductors

Phan Van Nham (1), Nguyen Huu Nha (2)

(1) Institute of Research and Development, Duy Tan University (2) Department of Theoretical Physics, VNUHCM-University of Science

The magnetic properties such as ferromagnetic (FM), antiferromagnetic (AFM) instabilities and especially spin fluctuations in diluted magnetic semiconductors are addressed. In the framework of the dynamical mean-field theory, we have found a set of self-consistent equations determining a single-particle Green's function of itinerant carriers of the Kondo lattice models. The magnetization, static and dynamical spin susceptibility functions and then the spin-relaxation rate are evaluated. Our results realize that once the impurity band is partly filled, the system settles in the FM state in case of low temperatures with sufficiently large magnetic coupling. That magnetic order would be replaced by the AFM state in case the impurity band is completely filled. Results of the dynamical spin susceptibility function address the strong spin fluctuations if the temperature reaches the transition value, especially for the situation of large magnetic coupling between the itinerant carrier spin and localized magnetic moments. In this case, the non-linear behavior of the nuclear spin-lattice relaxation rate versus temperature is found indicating the formation of the magnetic coherent bound state or the magnetic clusters before the magnetic ordered transition happens, the spin dynamical properties in DMS thus have been discussed in more profound.

Presenter: Phan Van Nham