tag:blogger.com,1999:blog-5439168179960787195.post3723000803582132592..comments2024-03-28T17:13:01.117+10:00Comments on Condensed concepts: Dimensionless ratios for metals III: LorenzRoss H. McKenziehttp://www.blogger.com/profile/09950455939572097456noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-5439168179960787195.post-64409515610276364052009-05-31T23:06:10.115+10:002009-05-31T23:06:10.115+10:00Piers,
Thanks for the interest,
I agree that the...Piers,<br /><br />Thanks for the interest,<br /><br />I agree that the case for the two-dimensionality at milliKelvin T is questionable.<br /><br />One response I would make is that the WF violation in CeCoIn5 was reported only for very low T, at fields close to the 5T QCP, and only with current perpendicular to the conducting layers. On the other hand, T-linear resistivity is seen over a wide temperature and field range and for current in either direction (at least above a few Kelvin). <br /><br />So, one could argue that inelastic scattering from 2D spin fluctuations could make an important low-T contribution to deviations from the WF law--and examine this effect without tackling the problem of the far-more-robust T-linear resistivity. The fact that a naive calculation using a 2D SDW picture accounts very well for the characteristic temperature and field dependence of deviations from the WF law gives some justification for this after the fact. <br /><br />If WF violation can be thus explained then one can re-examine transport phenomena over larger T scales using models in which quasiparticles remain intact.Unknownhttps://www.blogger.com/profile/05410107734176990734noreply@blogger.comtag:blogger.com,1999:blog-5439168179960787195.post-22231043296788254632009-05-12T12:28:00.000+10:002009-05-12T12:28:00.000+10:00Ross:
Great idea to start a Condensed Matter Blo...Ross: <br /><br />Great idea to start a Condensed Matter Blog. I've haven't had chance to read your paper with Michael Smith. It has many elements in common with the old work of Paul and Kotliar, and I was surprised that you did not reference this work!<br /><br />I have many issues with the "2D" spin fluid idea. But my main objection - is simply - why should we expect the spin fluid to be 2D in intermetallic systems that are in essence, three dimensional? Indeed - the recent measurements by the Los Alamos group show that near the QCP of the closely related CeRhIn5, the transport anisotropies become smaller, rather than larger.<br />Even in frustrated systems, one expects a cross-over to 3D behaviour at low T. Any reasonable estimate of such cross-over scales would be unable to account for the 200:1 resistance ratio over the full range of the linear resistivity. <br /><br />My more serious concern however, is the growing<br />suspicion that we are not just dealing with a quantum critical point, but that there are strong experimental signs of a strange metal phase between the Fermi liquid and the antiferromagnet. Indications to this effect are present in YRS (doped with Ge and with Ir), and in YbAlB4. <br /><br />Well. Thats a quick comment to get things going. <br /><br />But a very interesting paper and I look forward to more discussion.Piers Colemanhttps://www.blogger.com/profile/14595901752473864838noreply@blogger.com