Dynamics and relaxation in spin nematics

Мова статті: 
Англійська
Автор(и) статті: 
V. G. Bar'yakhtar, V. I. Butrim, A. K. Kolezhuk, and B. A. Ivanov
Вихідні данні статті: 
Phys. Rev. B vol. 87, Issue 22, 224407 (2013) [9 pages]
Назва журналу: 
Physical Review B
Рік публікації: 
2013
Volume: 
87
Issue: 
22
Ключові слова: 
phenomenology, dynamics, relaxation, spin nematics
Ключове слово: 
phenomenology
Ключове слово: 
dynamics
Ключове слово: 
relaxation
Ключове слово: 
spin nematics
We study the dynamics and relaxation of elementary excitations (magnons) in the spin nematic (quadrupole ordered) phase of S=1 magnets. We develop a general phenomenological theory of spin dynamics and relaxation for spin-1 systems. The results of the phenomenological approach are compared to those obtained by microscopic calculations for the specific S=1 model with isotropic bilinear and biquadratic exchange interactions. This model exhibits a rich behavior depending on the ratio of bilinear and biquadratic exchange constants, including several points with an enhanced symmetry. It is shown that symmetry plays an important role in relaxation. Particularly, at the SU(3) ferromagnetic point the magnon damping Γ depends on its wave vector k as Γk4, while a deviation from the high-symmetry point changes the behavior of the leading term to Γk2. We point out a similarity between the behavior of magnon relaxation in spin nematics to that in an isotropic ferromagnet.
Назва підрозділу: 
Кафедра математики, теоретичної фізики і комп-рних технологій
ІНСТИТУТ ВИСОКИХ ТЕХНОЛОГІЙ Матеріали дозволено використовувати на умовах GNU FDL без незмінюваних секцій та Creative Commons Attribution/Share-Alike
Дизайн: Інститут високих технологій
Ivan Ivanov