Spectral properties of doped bilayer cuprates at finite temperatures

Pramana

Amit Pratap¹  S K Joshi1 2¹  Ratan Lal¹  Govinda1¹ 

[1] Theory Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110 012, India$$

关键词: Doped bilayer cuprates;    spectral properties;    self-consistent perturbation approach.;   

DOI  :  

学科分类：物理（综合）

来源: Indian Academy of Sciences

【 摘 要 】

Recently, angle-resolved photoemission spectroscopy measurements on Bi2Sr2CaCu2O8+𝛿, which possesses two CuO2 layers in the same unit cell, have yielded very interesting results. For the overdoped samples, these results show a splitting of electronic states near 𝑘 = (𝜋,0) point of Brillioun zone. On the other hand, no splitting is observed in the underdoped samples. In view of this, the detailed studies including the doping and temperature dependence of the spectral properties become desirable. In this paper, we consider cuprates possessing two CuO2 layers per unit cell. Each layer in the system is described by the 𝑡-𝑡'-𝐽 model and the two layers are coupled via an intrabilayer hopping term (𝑡⊥) and an intrabilayer exchange coupling (𝐽⊥). A self-consistent perturbation approach is used to calculate the electronic spectral function for different values of hole density, hole momentum and temperature. We find that the imaginary part of the self energy is strongly momentum dependent which contradicts the suggestion that the Fermi surface of cuprates may be described by marginal Fermi liquid theory. We have calculated the spectral function for various values of intrabilayer parameters 𝑡⊥ and 𝐽⊥. For larger values of intrabilayer interactions we observe the splitting in the quasi-particle peak at 𝑘 = (𝜋,0) which is in agreement with the recent observations. The splitting is also found to be sensitive to the hole concentration as well as the temperature of the system. We have also discussed the reasons why the splitting is absent in underdoped bilayer cuprates at low temperature.

【 授权许可】

Unknown