Programme

P.9 -- Poster, NCTP-43

Date: Tuesday, 31 July 2018

Time: 08:30 - 10:00

Thermodynamic properties and excitation spectrum of Heisenberg spin chain with antiferromagnetic - ferromagnetic interactions

Pham Huong Thao

Faculty of Physics, University of Education, Hue Unuversity

Thermodynamic properties of antiferromagnetic spin chain with various nearest-neighbor and next-nearest-neighbor exchange interactions are studied using functional integral method in $J_1$ - $J_2$ Heisenberg model. Besides, the excitation spectrum of the system is also given. The results show that the system has two distinct excitations, one is gapless and the other is gapped from the ground state. The gapless branch which is related to combination of the two next nearest spins shows a quadratic dispersion relation in small $k_z$ region. The gapped one is concerned combination of the two nearest spins. Changing the exchange parameters $\alpha$ and $\beta$ influences on the thermodynamic properties and the excitation spectra of the system.

Presenter: Pham Huong Thao

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