Anomalous temperature dependence of charge-transfer excitation in the undoped cuprate Sr2CuO2Cl2

被引：35

作者：

Choi, HS ^{[1
]}

Lee, YS

Noh, TW

Choi, EJ

Bang, Y

Kim, YJ

机构：

[1] Seoul Natl Univ, Dept Phys, Seoul 151742, South Korea

[2] Seoul Natl Univ, Condensed Matter Res Ctr, Seoul 151742, South Korea

[3] Univ Seoul, Dept Phys, Seoul 130742, South Korea

[4] Chonnam Natl Univ, Dept Phys, Kwangju 500757, South Korea

[5] MIT, Ctr Mat Sci & Engn, Cambridge, MA 02139 USA

来源：

PHYSICAL REVIEW B | 1999年 / 60卷 / 07期

关键词：

D O I：

10.1103/PhysRevB.60.4646

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We investigated the temperature dependence of optical excitations of Sr2CuO2Cl2 in a temperature region of 10-523 K, using optical reflection and transmission measurements. Two peaks were found around 2.0 and 2.5 eV, and assigned as charge-transfer excitations related to a strongly correlated Zhang-Rice band and a nonbonding oxygen band, respectively. While the temperature dependence of the 2.5 eV peak can be explained by the lattice expansion effect, that of the 2.0-eV peak cannot; the latter redshifts by as much as 150 meV, while one would expect a blueshift of 10 meV from the lattice expansion. This observation is closely related to single-hole dynamics in cuprates. We suggest magnetism, or spin disordering with increasing temperature, as an origin of the anomalous temperature dependence. Comparisons with various many-body numerical calculations are also made. [S0163-1829(99)11431-0].

引用

页码：4646 / 4652

页数：7