A theoretical study of the long-range-disorder mixed-spin antiferromagnet L2BaNiO5

Autor:	Hongyan Kong, Lin Zhang
Rok vydání:	2006
Předmět:	Physics Range (particle radiation) Condensed matter physics Spins Heisenberg model Antiferromagnetism Condensed Matter::Strongly Correlated Electrons Spin (physics) Néel temperature Excitation Ion
Zdroj:	Science in China Series G: Physics, Mechanics and Astronomy. 49:576-587
ISSN:	1862-2844 1672-1799
DOI:	10.1007/s11433-006-2013-z
Popis:	In this paper, we introduce a quasi-one-dimensional S = 1 antiferromagnet Heisenberg model, and some physical properties of antiferromagnet L2BaNiO5 without antiferromagnet long-range-order above the Neel temperature are analyzed based on the frame of two-time Green’s function theory. In a high temperature region, we calculate the correlation functions, and obtain excitation spectrum along Ni chains and the Haldane gap in this spectrum versus temperature. We find that the short-range correlation still exists at high temperature, which leads to the existence of Haldane gap in excitation spectrum. The increment of excitation energy in the spectrum along the Ni chain is found to be induced by the AF interaction between spins of rare-earth and Ni ions. Additionally, we also find that Haldane gap goes up with temperature increasing.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::5029dab75500ca6fc16d2e8b6ae3e9c8 https://doi.org/10.1007/s11433-006-2013-z Zobrazit plný text záznamu