超導體物理

Condensed matter near a second order phase transition is accurately described within the generalized Ginzburg - Landau - Wilson approach to condensed matter physics. Building blocks of this phenomenological method on the mesoscopic scale are the order parameter field and the symmetry that is “spontaneously broken” along the transition line. Examples include magnetic systems (ferromagnets, antiferromagnets) superconductor, superfluid and other Bose condensates, liquid crystals and many others. In the present course I concentrate on superconductors as a prime example with emphasis on high temperature superconductivity. 1. Introduction: old and new superconductivity phenomena. Superconductivity is introduced both phenomenologically and microscopically (no quantum background is necessary since detailed microscopic theory is out of scope of the present course). Moreover it is demonstrated that even now we do not have a microscopic theory for probably all kinds of the highTc superconductors and are forced to use the phenomenological Ginzburg-Landau-Wilson approach. 2. Phase transitions and the mean field theory. The low temperature phase generally exhibits phase coherence on the mesoscopic scale and possesses topological solitons (often termed “vortices”). Especial attention in paid to situation in superconductors in magnetic fields, rotated superfluids and liquid crystals in which stable soliton lattices are formed. 3. Thermal fluctuations. They generally lead to excitation of phonons in solids and liquids, but in addition influence greatly the order parameter and properties of vortex matter. It is especially important in 2D systems. For example the vortex lattice melts into the vortex liquid. Kosterlitz – Thouless transition in 2D systems (like layered high Tc cuprates) is another manifestation of strong thermal fluctuation. 4. Dynamics Is described within the time dependent Ginzburg - Landau approach (called in other systems also as a type A dynamics). It exhibits wide range of phenomena from flux flow, thermal quench dynamics to dendrites in explosive flux penetration. 5. Quenched disorder It is either naturally present or created artificially.Disorder qualitatively modifies static and especially dynamical properties of these systems leading to creation of “glassy” phases and finite critical current in superconductors.

Electrodynamics and statistical physics are required. Quantum physics is not required since the Ginzburg - Landau approach to condensed matter physics is used. Condensed matter introductory course is preferable but not necessary.

Exercises from my textbook presented in the class, in addition there is an option to make a presentation.

1. B. Rosenstein and D. P. Li, “Ginzburg - Landau description of the quantum condensate and its topological matter”, CambridgeUniversityPress , (in print, .pdf is available). 2. W. Buckel and R. Kleiner, “Superconductivity”, Willey – Verlag, Darmstadt (2004). Introductory with emphasis on applications of superconductors. 537.623 BUC in library.

地點

SC 160

時間

Initial F 13.20

聯絡方式

vortexbar@yahoo.com