%0 Book Section %1 statphys23_0234 %A Malard, M. %B Abstract Book of the XXIII IUPAP International Conference on Statistical Physics %C Genova, Italy %D 2007 %E Pietronero, Luciano %E Loreto, Vittorio %E Zapperi, Stefano %K antiferromagnetic chains coupling decay energy function green magnon-phonon phonons spin-1 statphys23 technique topic-8 %T Influence of Magnon-Phonon Coupling on the Phonon Dynamics of One-dimensional Antiferromagnets %U http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=234 %X The interplay between magnetic and elastic degrees of freedom, the so-called magnon-phonon coupling, plays an important role in magnetism. The research on this area has been stimulated by the belief that magnon-phonon interaction can be the relevant mechanism behind a variety of frontier problems, both in theoretical and experimental physics. The existence of an excitation gap and a finite correlation lenght for integer spin antiferromagnetic (AFM) chains is, by now, well established theoretically, numerically and experimentally. Indeed, the low dimensional spin-1 antiferromagnets in the presence of external fields, with anisotropies and dimerization are now abundantly addressed in the literature. Recently, it became generally accepted that, on top of all the preeceding interactions, the frustration of the spin lattice can be caused by lattice fluctuations coupled to the spin system as well. Yet, the dynamics of spin-1 AFM chains coupled to phonons has not been suficiently explored. It is well known that the spin-1/2 AFM chain coupled to phonons develops a spin gap via the dimerization of the lattice. This is known as the spin-Peierls effect. Although Schulz has shown that we cannot expect a spin-Peierls instability for a integer spin chain, we believe that the effects due to the magnon-phonon coupling play a important role for the dynamics of such systems. This is the subject of the present work. This research can be justified both theoretically and experimentally. Besides adding to the conceptual background of magnetoelastic phenomena in low-dimensional magnets, it also helps understanding the new behaviors revealed by many recent materials. High-temperature superconductivity is probably the most prominent example in this scenario. The Green's function technique is used to investigate the phonon dynamics of one-dimensional antiferromagnets within the framework of an interaction Heisenberg hamiltonian. This is treated via Holstein-Primakoff transformations in the context of the modified spin wave theory of Takahashi. The obtained phonon's relaxation function provides a measure of the effect of magnon-phonon coupling on phonon's decay and dispersion law.

@incollection{statphys23_0234, abstract = {The interplay between magnetic and elastic degrees of freedom, the so-called magnon-phonon coupling, plays an important role in magnetism. The research on this area has been stimulated by the belief that magnon-phonon interaction can be the relevant mechanism behind a variety of frontier problems, both in theoretical and experimental physics. The existence of an excitation gap and a finite correlation lenght for integer spin antiferromagnetic (AFM) chains is, by now, well established theoretically, numerically and experimentally. Indeed, the low dimensional spin-1 antiferromagnets in the presence of external fields, with anisotropies and dimerization are now abundantly addressed in the literature. Recently, it became generally accepted that, on top of all the preeceding interactions, the frustration of the spin lattice can be caused by lattice fluctuations coupled to the spin system as well. Yet, the dynamics of spin-1 AFM chains coupled to phonons has not been suficiently explored. It is well known that the spin-1/2 AFM chain coupled to phonons develops a spin gap via the dimerization of the lattice. This is known as the spin-Peierls effect. Although Schulz has shown that we cannot expect a spin-Peierls instability for a integer spin chain, we believe that the effects due to the magnon-phonon coupling play a important role for the dynamics of such systems. This is the subject of the present work. This research can be justified both theoretically and experimentally. Besides adding to the conceptual background of magnetoelastic phenomena in low-dimensional magnets, it also helps understanding the new behaviors revealed by many recent materials. High-temperature superconductivity is probably the most prominent example in this scenario. The Green's function technique is used to investigate the phonon dynamics of one-dimensional antiferromagnets within the framework of an interaction Heisenberg hamiltonian. This is treated via Holstein-Primakoff transformations in the context of the modified spin wave theory of Takahashi. The obtained phonon's relaxation function provides a measure of the effect of magnon-phonon coupling on phonon's decay and dispersion law.}, added-at = {2007-06-20T10:16:09.000+0200}, address = {Genova, Italy}, author = {Malard, M.}, biburl = {https://www.bibsonomy.org/bibtex/255a7b235662651e2a4bff7b8c645b2af/statphys23}, booktitle = {Abstract Book of the XXIII IUPAP International Conference on Statistical Physics}, editor = {Pietronero, Luciano and Loreto, Vittorio and Zapperi, Stefano}, interhash = {cf10b49bc7a5d665ef15cd2e58698a37}, intrahash = {55a7b235662651e2a4bff7b8c645b2af}, keywords = {antiferromagnetic chains coupling decay energy function green magnon-phonon phonons spin-1 statphys23 technique topic-8}, month = {9-13 July}, timestamp = {2007-06-20T10:16:14.000+0200}, title = {Influence of Magnon-Phonon Coupling on the Phonon Dynamics of One-dimensional Antiferromagnets}, url = {http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=234}, year = 2007 }