Frustrated spin chains in strong magnetic field: Dilute two-component Bose gas regime

Мова статті: 
Автор(и) статті: 
A. K. Kolezhuk, F. Heidrich-Meisner, S. Greschner, and T. Vekua
Вихідні данні статті: 
Phys. Rev. B Vol. 85, Issue 6, Article No. 064420 (2012) [17 pages]
Назва журналу: 
Physical Review B
Рік публікації: 
Ключові слова: 
frustrated spin chains, strong magnetic field, dilute Bose gas, two-component bosons, vector chirality
Ключове слово: 

We study the ground state of frustrated spin-S chains in a strong magnetic field in the immediate vicinity of saturation. In strongly frustrated chains, the magnon dispersion has two degenerate minima at inequivalent momenta ±Q, and just below the saturation field the system can be effectively represented as a dilute one-dimensional lattice gas of two species of bosons that correspond to magnons with momenta around ±Q. We present a theory of effective interactions in such a dilute magnon gas that allows us to make quantitative predictions for arbitrary values of the spin. With the help of this method, we are able to establish the magnetic phase diagram of frustrated chains close to saturation and study phase transitions between several nontrivial states, including a two-component Luttinger liquid, a vector chiral phase, and phases with bound magnons. We study those phase transitions numerically and find a good agreement with our analytical predictions. Full text is available here.

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