tag:blogger.com,1999:blog-5439168179960787195.post3294176031500131610..comments2024-03-28T17:13:01.117+10:00Comments on Condensed concepts: Spin nematic fluctuations and elastic anomalies.Ross H. McKenziehttp://www.blogger.com/profile/09950455939572097456noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-5439168179960787195.post-68361158785611264252011-03-05T03:28:52.203+10:002011-03-05T03:28:52.203+10:00We were glad to hear about our work in the blog! R...We were glad to hear about our work in the blog! Regarding the two points raised, here are a few thoughts:<br /><br />1) In our measurements, due to sample size limitations, we could not resolve the full elastic tensor. However, there is a paper in arxiv (1008.1479) where Yoshizawa et al measure all the elastic components. They observe a softening in some other moduli as well, but smaller than the softening in C66. Further evidence for the connection between the lattice softening and nematic fluctuations is that, for highly doped samples, we actually observed a mild increase in the resonant frequencies as the temperature was decreased.<br /><br />2) That's an interesting point. Note that, in our model, what drives the structural transition are the magnetic fluctuations, precisely through the magneto-elastic coupling. In most materials, one usually has the coupling between the squared magnetization and the longitudinal distortion. In the pnictides, by symmetry, there is a direct coupling between the shear distortion and the nematic order parameter (m1.m2). Then, the onset of nematic ordering coincides with the structural transition. Notice also that the hardening of the shear modulus below Tc is an unexpected feature, since there is no nearby structural instability. In our model, it is naturally explained by the presence of nematic fluctuations and the competition between magnetism and superconductivity.<br /><br />Rafael Fernandes, Premala Chandra, David Mandrus, and Joerg SchmalianRafael Fernandeshttps://www.blogger.com/profile/11765851960771665776noreply@blogger.com