Elasticity and melting of vortex crystals in anisotropic superconductors: Beyond the continuum regime
نویسندگان
چکیده
The elastic moduli of vortex crystals in anisotropic superconductors are frequently involved in the investigation of their phase diagram and transport properties. We provide a detailed analysis of the harmonic eigenvalues ~normal modes! of the vortex lattice for general values of the magnetic field strength, going beyond the elastic continuum regime. The detailed behavior of these wave-vector-dependent eigenvalues within the Brillouin zone ~BZ!, is compared with several frequently used approximations that we also recalculate. Throughout the BZ, transverse modes are less costly than their longitudinal counterparts, and there is an angular dependence which becomes more marked close to the zone boundary. Based on these results, we propose an analytic correction to the nonlocal continuum formulas which fits quite well the numerical behavior of the eigenvalues in the London regime. We use this approximate expression to calculate thermal fluctuations and the full melting line ~according to Lindeman’s criterion! for various values of the anisotropy parameter.
منابع مشابه
Vortex liquid crystals in anisotropic type II superconductors.
In an isotropic type II superconductor in a moderate magnetic field, the transition to the normal state occurs by vortex lattice melting. In certain anisotropic cases, the vortices acquire elongated cross sections and interactions. Systems of anisotropic, interacting constituents generally exhibit liquid crystalline phases. We examine the possibility of a two step melting in homogeneous type II...
متن کاملComment on vortex liquid crystal in anisotropic type II superconductors.
Comment on " Vortex Liquid Crystal in Anisotropic Type II Superconductors " Recently Carlson et al. [1] tried to compose the H − T phase diagram of anisotropic superconductors based on the Lindemann criterion for melting of flux-line lattice. It is worthy to notice that the issue itself is interesting. However, their conclusion on the existence of a smectic vortex phase is unphysical for the fo...
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Comment on " Vortex Liquid Crystal in Anisotropic Type II Superconductors " The suppression of superconductivity in type II superconductors is associated with the melting transition of the lattice of flux quanta [1, 2, 3]. Most melting phenomena in Nature are thermodynamic first-order phase transitions. An analytic description of melting is thus difficult since there is no good handle, such as ...
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