TY - JOUR
T1 - The universality of pseudogap phenomenon in the normal state of high temperature cuprate superconductors
AU - Lam, C. C.
AU - Vyas, Anand
PY - 2001/6/30
Y1 - 2001/6/30
N2 - The pseudogap phenomenon in the normal state of Sn-, Mg- and Cd-doped Hg-1223 ceramic superconductors was studied based on the results of resistivity versus temperature measurement. By using the data obtained in the resistivity measurement a logarithmic deviation of the conductivity versus inverse temperature, i.e. ln[σ(T) - σN (T)] versus 1/T was constructed to study the pseudogap which is opened at T* far above the critical temperature TC of the superconductors. The magnitude of the pseudogap was measured through the slope of the linear part in these plots. It is surprising that the differentiation of these plots with respect to the inverse temperature shows a constant within very wide temperature range. Similar as in the energy gap measurement in the semi-conductors, this constant should represent the pseudogap of the normal state for the materials interested. The occurrence of the characteristic temperatures T*, TS and TF can be interpreted by our microscopic theory. The physical significances of the variation in the magnitude of the pseudogap ΔPG with respect to temperature are related to the kinetic energy of the quasiparticles involved in the system. The plot of T* against the molar fraction of the Sn-doping x is linear. However, the data of T* for the other doping elements Mg and Cd are scattered from the linear relationship for the Sn-doped (Hg1-x, Snx)-1223 system. However, when we plot the relationship between T* against TC, the data of T* for different doping elements fall on the same curve of bend finger-like shape. This indicates that the intrinsic parameters T* and TC satisfy a universal relationship. The ratio ΔPG/(κBTF) is expressible as a linear function of TC when the critical temperature is below ∼ 129 K; while for samples that have critical temperature greater than 129 K this ratio is expressible as a quadratic polynomial function of TC. The universality relationship is also hold for this ratio against TC.
AB - The pseudogap phenomenon in the normal state of Sn-, Mg- and Cd-doped Hg-1223 ceramic superconductors was studied based on the results of resistivity versus temperature measurement. By using the data obtained in the resistivity measurement a logarithmic deviation of the conductivity versus inverse temperature, i.e. ln[σ(T) - σN (T)] versus 1/T was constructed to study the pseudogap which is opened at T* far above the critical temperature TC of the superconductors. The magnitude of the pseudogap was measured through the slope of the linear part in these plots. It is surprising that the differentiation of these plots with respect to the inverse temperature shows a constant within very wide temperature range. Similar as in the energy gap measurement in the semi-conductors, this constant should represent the pseudogap of the normal state for the materials interested. The occurrence of the characteristic temperatures T*, TS and TF can be interpreted by our microscopic theory. The physical significances of the variation in the magnitude of the pseudogap ΔPG with respect to temperature are related to the kinetic energy of the quasiparticles involved in the system. The plot of T* against the molar fraction of the Sn-doping x is linear. However, the data of T* for the other doping elements Mg and Cd are scattered from the linear relationship for the Sn-doped (Hg1-x, Snx)-1223 system. However, when we plot the relationship between T* against TC, the data of T* for different doping elements fall on the same curve of bend finger-like shape. This indicates that the intrinsic parameters T* and TC satisfy a universal relationship. The ratio ΔPG/(κBTF) is expressible as a linear function of TC when the critical temperature is below ∼ 129 K; while for samples that have critical temperature greater than 129 K this ratio is expressible as a quadratic polynomial function of TC. The universality relationship is also hold for this ratio against TC.
UR - http://www.scopus.com/inward/record.url?scp=0035973638&partnerID=8YFLogxK
U2 - 10.1142/S0217979201006598
DO - 10.1142/S0217979201006598
M3 - Article
AN - SCOPUS:0035973638
SN - 0217-9792
VL - 15
SP - 2285
EP - 2300
JO - International Journal of Modern Physics B
JF - International Journal of Modern Physics B
IS - 16
ER -