Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 18: Superconductivity - Properties, Electronic Structure, Order Parameter II
TT 18.10: Vortrag
Montag, 7. März 2005, 12:45–13:00, TU H2053
Thermoelectric power of V3Si single crystal near the structural transition — •Jun Sung Kim and Reinhard K Kremer — MPI-FKF, 70569 Stuttgart
V3Si, one of the A-15 superconductors, has attracted a lot of interest in experimental and theoretical studies because of the relatively high superconducting transition temperature and the unclear role of the lattice instability. The structural phase transition from cubic to tetragonal occurs at TM ∼ 23 K, just above the superconducting transition TC = 16.7 K. To study the implication of the structural phase transition on the electronic properties, we have carried out highly temperature resolved thermoelectric power measurements in the regime of the structural transition on a single crystal which according to heat capacity measurements shows a clear transition at TM. Above TM, the thermoelectric power (S) shows a nonlinear temperature dependence with a knee structure near T ∼ 100 K, which is consistent with previous measurements on polycrystalline samples.[1] However, it is found that there is a clear slope change in S(T) near TM on the single crystal, and S(T) rapidly decreases below TM. These results indicate that the scattering asymmetry between hole and electron is reduced due to the structural phase transition. The change of the density of states near the Fermi level and electron-phonon coupling will be discussed as an origin of temperature dependence of S(T).
[1] M. P. Sarachik, et al. Can. J. Phys. 41, 1542 (1963).