Bibliographic Details
| Title: |
SPIN-CROSSOVER IN MOLECULAR CRYSTALS: AN ELECTRON-COUPLED LOCAL VIBRATIONS MODEL. |
| Alternate Title: |
TRANSICIÖN DE ESPÍN EN CRISTALES MOLECULARES: UN MODELO DE ELECTRONES Y VIBRACIONES LOCALES ACOPLADAS. |
| Authors: |
RODRÍGUEZ-CASTELLANOS, C.1,2 crc@fisica.uh.cuy, PLASENCIA, Y.1, REGUERA, E.1 |
| Source: |
Revista Cubana de Física. dic2018, Vol. 35 Issue 2, p91-96. 6p. |
| Subjects: |
MOLECULAR crystals, SPIN crossover, VIBRATION (Mechanics), SINGLE molecule magnets, MAGNETISM, ELECTRONS |
| Abstract (English): |
A model of eg electrons at octahedral sites coupled to local vibrational "breathing" modes interacting with its near neighbors is proposed to describe spin-crossover (SCO) in molecular crystals. Decoupling vibrations leads to an effective electron Hamiltonian with renormalized site energies, where ferromagnetic and antiferromagnetic, short range and long range electron-electron interactions arise in a natural way. An exact analytic expression for the free energy functional is derived. A phase diagram for homogenous phases, describing the basic phenomenology of SCO is obtained and the transition temperatures are expressed in terms of model parameters. Under appropriate conditions, two-step transitions are found to take place for systems with both, short range and long range interactions. Stability with respect to spatial fluctuations is discussed. [ABSTRACT FROM AUTHOR] |
| Abstract (Spanish): |
Para describir la transición de espín (SCO) en cristales moleculares se propone un modelo de electrones eg acoplados a modos de vibración locales "respiratorios" que interact úan con sus vecinos próximos. Al desacoplar las vibraciones resulta un Hamiltoniano electrónico efectivo con energías renormalizadas, donde las interacciones electr ón-electrón ferromagnéticas y anti-ferromagnéticas, de corto y de largo alcance aparecen de modo natural. Se deriva una expresión analítica exacta para el funcional de energía libre. Se obtiene un diagrama de fases homogéneas que describe la fenomenología básica de la transición de espín y se calculan las temperaturas de transición en función de los parámetros del modelo. Bajo condiciones apropiadas, las transiciones en dos pasos resultan posibles tanto en sistemas con interacciones de corto como de largo alcance. Se discute la estabilidad respecto a las fluctuaciones espaciales. [ABSTRACT FROM AUTHOR] |
|
Copyright of Revista Cubana de Física is the property of Universidad de La Habana and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) |
| Database: |
MedicLatina |
