Temperature dependence of Temperature dependence of chemical potential in Bi2212chemical potential in Bi2212

試料 Bi2Sr2-xLaxCaCu2O8+d

= 0.02, 0.03, 0.05, 0.06,

Bi2Sr2Y0.2Ca0.8Cu2O8+d

= 0.08, 0.15(Tc ～ 30 K, 85 K)

測定・ XPS 励起光 Mg K 線 (1253.6 eV) 分解能　 0.7 eV T = 8.5 K, 100 K, 200 K, 300 K

・ ARPES 励起光　 19 eV 分解能 14 meV T= 10 K, 100K, 200K, 300K

ExperimentExperiment

Temperature Dependence of Core-level Spectra (Temperature Dependence of Core-level Spectra (=0.02)=0.02)

Temperature Dependence of Core-level Spectra (Temperature Dependence of Core-level Spectra (=0.03)=0.03)

Temperature Dependence of Core-level Spectra (Temperature Dependence of Core-level Spectra (=0.05)=0.05)

Temperature Dependence of Core-level Spectra (Temperature Dependence of Core-level Spectra (=0.06)=0.06)

Temperature Dependence of Core-level Spectra (Temperature Dependence of Core-level Spectra (=0.08)=0.08)

Temperature Dependence of Core-level Spectra (Temperature Dependence of Core-level Spectra (=0.15)=0.15)

Temperature Dependence of Energy Position ITemperature Dependence of Energy Position I(Relative to energy at 8.5 K)(Relative to energy at 8.5 K)

ホールのドープとともに温度変化によるシフト量が抑制

Temperature Dependence of Energy Position IITemperature Dependence of Energy Position II

Temperature Dependence of Energy Position IIITemperature Dependence of Energy Position III(Relative to energy at (Relative to energy at =0.06)=0.06)

非超伝導相ではすべての元素が同じ方向にシフトし超伝導相で Sr 以外は逆にシフト

0.4

0.2

0.0

-0.2

Ch

em

ica

l Po

tent

ial S

hift

(e

V)

0.300.250.200.150.100.050.00

Hole concentration

Sr_8.5K (Experiment) Sr_100K Sr_200K Sr_300K T = 200 K (t-J model) T = 400 K T = 600 K T = 800 K T = 1000 K

Comparison with Theoretical WorksComparison with Theoretical Works

J. Jaklic and P. Prelovsek, PRL. 77, 892 (1996)

=0.03

Temperature dependence of valence band spectra ITemperature dependence of valence band spectra I

Core-levelと同程度のシフト

=0.08

Temperature dependence of valence band spectra IITemperature dependence of valence band spectra II

=0.03に比べてわずかな変化

Hysteresis (Doping Dependence)Hysteresis (Doping Dependence)(Low→High→Low Temperature)(Low→High→Low Temperature)