Doping dependence of the optical properties of Ba1-xKxBiO3

被引:41
作者
Puchkov, AV
Timusk, T
Karlow, MA
Cooper, SL
Han, PD
Payne, DA
机构
[1] UNIV ILLINOIS,DEPT PHYS,URBANA,IL 61801
[2] UNIV ILLINOIS,MAT RES LAB,URBANA,IL 61801
[3] UNIV ILLINOIS,DEPT MAT SCI & ENGN,URBANA,IL 61801
来源
PHYSICAL REVIEW B | 1996年 / 54卷 / 09期
关键词
D O I
10.1103/PhysRevB.54.6686
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We analyze the doping dependence of the optical conductivity of the Ba1-xKxBiO3 (BKBO) system in the full doping range from x=0 to x=0.46. We have used the results of our reflectivity and ellipsometric measurements at x=0.31, 0.38, 0.4, 0.46, as well as the results obtained by other experimental groups at different doping levels, to analyze the doping dependence of the spectral weight distribution. At the insulator-metal transition boundary we observe the appearance of a Drude-like free-carrier peak in the optical conductivity. In the metallic phase, we have performed measurements in the normal as well as the superconducting state. The data show that BKBO becomes a better metal with increasing x in the metallic regime due to a decrease in the scattering rate of the metallic charge carriers, while the density of the mobile (Drude) charge carriers does not significantly change with doping. The London penetration depth lambda(L) is also found to be almost doping (and T-c) independent while the superconducting gap scales with T-c as 2 Delta(s)/k(b)T(c)=4.2+/-0.3.
引用
收藏
页码:6686 / 6692
页数:7
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