A new class of materials known as so-called "bad metals" show transport properties not understandable using conventional transport theory. Their resistivities at high temperatures imply electron mean free paths less than an inter-atomic distance, and their infrared conductivity is not in agreement with conventional Drude theory. We are using SrRuO3 as a model system to study this phenomenon.
DC conductivity measurements on SrRuO3 films reveal some anomalous behavior. The resistance at high temperatures continues to rise linearly with temperature beyond the point where conventional theories are no longer applicable Measurements of the frequency dependent conductivity by infrared reflectivity and terahertz time-domain spectroscopy, show an analytic structure fundamentally different from that predicted by the standard theory of metals. The low temperature resistance incrased like T2, as expected from electron-electron scattering. Residual resistivities achieved are comparable to the best single crystal values.
L. Klein, J.S. Dodge, C.H. Ahn, T.H. Geballe, M.R. Beasley and A. Kapitulnik, "Anomalous spin scattering effects in the badly metallic itinerant ferromagnet SrRuO3," Phys. Rev. Lett. 77, 2774 (1996).
P. Kostic, Y. Okada, N.C. Collins, Z. Schlesinger, J.W. Reiner, L. Klein, A. Kapitulnik, T.H. Geballe, M.R. Beasley, "Non-Fermi-liquid behavior of SrRuO3: evidence from infrared conductivity," Phys. Rev. Lett. 81, 2498 (1998)
A.P. Mackenzie, J.W. Reiner, A.W. Tyler, L.M. Galvin, S.R. Julian, M.R. Beasley, T.H. Geballe, A. Kapitulnik, "Observation of quantum oscillations in the electrical resistivity of SrRuO3," Phys. Rev. B 58 , R13318 (1998)
J.S. Dodge, C.P. Weber, J. Corson, J. Orenstein, Z. Schlesinger, J.W. Reiner, M.R. Beasley, "Low-frequency crossover of the fractional power-law conductivity in SrRuO3," Phys. Rev. Lett. 85, 4932, (2000)
L. Klein, Y. Kats, N. Wiser, M. Konczykowski, J.W. Reiner, T.H. Geballe,
M.R. Beasley, A. Kapitulnik, "Negative deviations from Matthiessen's rule
for SrRuO3 and CaRuO3," Europhysics Letters 55
, 532, (2001)