Bulletin of the American Physical Society
2006 APS March Meeting
Monday–Friday, March 13–17, 2006; Baltimore, MD
Session U1: Spin Liquids and Superconductivity near the Mott Transition |
Hide Abstracts |
Sponsoring Units: DCMP Chair: Dunghai Lee, University of California, Berkeley Room: Baltimore Convention Center Ballroom IV |
Thursday, March 16, 2006 8:00AM - 8:36AM |
U1.00001: Spin Liquid States in the Hubbard Model: Implications for Organics Invited Speaker: We formulate a U(1) gauge theory of the Hubbard model in the slave-rotor representation. From this formalism it is argued that spin liquid phases may exist near the Mott transition in the Hubbard model on triangular and honeycomb lattices at half filling. The organic compound $\kappa $-(BEDT-TTF)$_{2}$Cu$_{2}$(CN)$_{3}$ is a good candidate for the spin liquid state on a triangular lattice. We predict a highly unusual temperature dependence for the thermal conductivity of this material. [Preview Abstract] |
Thursday, March 16, 2006 8:36AM - 9:12AM |
U1.00002: Spin liquid and superconductivity in two-dimensional organic charge transfer salts Invited Speaker: We introduce and analyze a variational wave function for quasi two-dimensional organic salts containing strong local and nonlocal correlation effects. We find an unconventional superconducting ground state for intermediate charge carrier interaction, sandwiched between a conventional metal at weak coupling and a spin liquid at larger coupling. Most remarkably, the excitation spectrum is dramatically renormalized and is found to be the driving force for the formation of the unusual superconducting state. [Preview Abstract] |
Thursday, March 16, 2006 9:12AM - 9:48AM |
U1.00003: Anomalous superconductivity near the Mott transition Invited Speaker: High-temperature superconductivity appears near an antiferromagnetic Mott insulating phase and a normal phase with a pseudogap. It was suggested early on by Anderson that the strong-coupling limit of the Hubbard model should contain the main physics. It is only recently that we have begun to have access to sufficiently accurate algorithms and powerful enough computers to begin to extract the main features of the phase diagram of high-temperature superconductors from the Hubbard model in a nearly quantitative manner. In this talk, the zero temperature phase diagram of the two-dimensional Hubbard model is discussed based on several ``quantum cluster'' approaches, mainly Variational Cluster Perturbation Theory [1] and Cellular Dynamical Mean Field Theory [2], that shall be introduced. The overall ground state phase diagram of the high-temperature superconductors as well as the asymmetric one-particle excitation spectra for both hole- and electron-doping are reproduced. The d-wave order parameter is found to assume a dome shape as a function of doping and to scale like the magnetic exchange coupling J for U comparable to the bandwidth. We stress the features of superconductivity that are non-BCS like due to the proximity to the Mott insulator. In stark contrast with BCS theory, the superconducting gap can decrease monotonically at the same time as the d-wave order parameter increases away from half-filling. Also, d-wave superconductivity is driven by a lowering of kinetic energy instead of potential energy, in conformity with experiments on cuprates. The pseudogap [3-5] and results of other approaches will also be briefly touched upon. \newline [1] David S\'{e}n\'{e}chal, P.-L. Lavertu, M.-A. Marois, and A.- M.S. Tremblay, Phys. Rev. Lett. \textbf{94}, 156404 (2005). \newline [2] S. S. Kancharla, M. Civelli, M. Capone, B. Kyung, D. Senechal, G. Kotliar, A.-M.S. Tremblay, cond-mat/0508205. \newline [3] B. Kyung, S.S. Kancharla, D. S\'{e}n\'{e}chal, A.-M.S. Tremblay, M. Civelli, and G. Kotliar cond-mat/0502565 \newline [4] B. Kyung, V. Hankevych, A.-M. Dar\'{e} et A.-M.S. Tremblay, Phys. Rev. Lett. \textbf{93}, 147004 (2004). \newline [5] A.-M.S. Tremblay, B. Kyung and David S\'{e}n\'{e}chal, cond-mat/0511334 [Preview Abstract] |
Thursday, March 16, 2006 9:48AM - 10:24AM |
U1.00004: The origin of the pseudogap in the high Tc superconductors Invited Speaker: The origin of the pseudogap is one of the most important questions in high Tc superconductors. The idea of circulating currents as being responsible for the pseudogap will be considered and various current paths through the Cu-O plane examined in the light of recent neutron scattering experiments. [Preview Abstract] |
Thursday, March 16, 2006 10:24AM - 11:00AM |
U1.00005: Polarized Neutron Diffraction to discover symmetry breaking in pseudogap region of Y(123)-Cuprate Invited Speaker: \vspace {0.5 cm} One of the leading issues in high-$T_C$ superconductors is the origin of the pseudogap phase in underdoped cuprates. Using polarized elastic neutron diffraction, we identify a novel magnetic order in the YBa$_2$Cu$_3$O$_{6+x}$ system$^*$. The observed magnetic order preserves translational symmetry as proposed for orbital moments in the circulating current theory of the pseudogap state (see C.M. Varma, at http://fr.arxiv.org/abs/cond-mat/0507214). To date, it is the first direct evidence of an hidden order parameter characterizing the pseudogap phase in high-$T_C$ cuprates. \\ $^*$ B. Fauqu\'e, Y.~Sidis, V.~Hinkov, S.~Pailh\`{e}s, C.T. Lin, X. Chaud and P.~Bourges, at http://fr.arxiv.org/abs/cond- mat/0509210. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700