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Based on the t-J model and slave-boson theory, we have studied the electronic structure in one-dimensional SrCuO2 by calculating the electron spectrum. Our results show that the electron spectra are mainly composed of three parts in one-dimensional SrCuO2, a sharp low-energy peak, a broad intermediate-energy peak and a high-energy peak. The sharp low-energy peak corresponds to the main band (MB) while the broad intermediate-energy peak and high-energy peak are associated with the shadow band (SB) and high-energy band (HB), respectively. From low-energy to intermediate-energy region, a clear two-peak structure (MB and SB) around the momentum Γ appears, and the distance between two peaks decreases along the momentum direction from Γ to π / 2 , then disappears at the critical momentum point k c , leaving a single peak above k c . The electron spectral function in one-dimensional SrCuO2 is also the doping and temperature dependent. In particular, in the very low doping concentration, the HB merges into the MB. However, with the increases of the doping concentration, the HB separates from the MB and moves quickly to the high-binding energy region. The HB and MB are the direct results of the spin-charge separation while SB is the result of strong interaction between charge and spin parts. Therefore, our theoretical result predicts that the HB is more likely to be found at the low doping concentration, and it will be drowned in the background when the doping concentration is larger. Then with the temperature increases, the magnitude of the SB decreases, and it disappears at high temperature. [ABSTRACT FROM AUTHOR]

Based on the t-J model and slave-boson theory, we have studied the electronic structure in one-dimensional SrCuO2 by calculating the electron spectrum. Our results show that the electron spectra are mainly composed of three parts in one-dimensional SrCuO2, a sharp low-energy peak, a broad intermediate-energy peak and a high-energy peak. The sharp low-energy peak corresponds to the main band (MB) while the broad intermediate-energy peak and high-energy peak are associated with the shadow band (SB) and high-energy band (HB), respectively. From low-energy to intermediate-energy region, a clear two-peak structure (MB and SB) around the momentum Γ appears, and the distance between two peaks decreases along the momentum direction from Γ to π / 2 , then disappears at the critical momentum point k c , leaving a single peak above k c . The electron spectral function in one-dimensional SrCuO2 is also the doping and temperature dependent. In particular, in the very low doping concentration, the HB merges into the MB. However, with the increases of the doping concentration, the HB separates from the MB and moves quickly to the high-binding energy region. The HB and MB are the direct results of the spin-charge separation while SB is the result of strong interaction between charge and spin parts. Therefore, our theoretical result predicts that the HB is more likely to be found at the low doping concentration, and it will be drowned in the background when the doping concentration is larger. Then with the temperature increases, the magnitude of the SB decreases, and it disappears at high temperature. [ABSTRACT FROM AUTHOR]

By considering the pseudogap effect, the doping and energy dependences of thermal conductivity in cuprate superconductors are studied. Our results show that the thermal conductivity as a function of energy exhibits a characteristic peak from underdoping to overdoping due to the presence of the pseudogap in pseudogap phase of cuprate superconductors. The thermal conductivity is strongly doping dependent. On the one hand, with increasing doping concentration, the weight of thermal conductivity increases quickly, especially the residual thermal conductivity which is in qualitative agreement with the experimental data. On the other hand, the characteristic energy corresponding to the position of the characteristic peak decreases monotonically upon increasing doping concentration, and it scales with the doping dependence of pseudogap. In particular, we have studied the doping dependence of the ratio of quasiparticle velocities normal and tangential to the Fermi surface at the nodes . It is shown that increases with the increase of doping concentration. Moreover, we explain that both the residual thermal conductivity and increase rapidly upon the increase in doping concentration in heavily overdoped cuprate superconductors. [ABSTRACT FROM AUTHOR]

There is a long-standing issue that the optical conductivity in normal-state of cuprate superconductors deviates the conventional Drude type marked by dependence, exhibiting two main components from underdoping to overdoping, a narrow band peaked around zero energy and a broadband centered in the mid-infrared region called mid-infrared band. Within the renormalized t- J model and self-consistent mean field theory, we discuss the doping and energy dependence of optical conductivity in cuprate superconductors. Our results show that the appearance of the pseudogap in normal state is responsible for anomalous optical conductivity, giving rise to the mid-infrared band. In particular, in analogy to the doping dependence of pseudogap, optical conductivity is also strongly doping dependent. By increasing the doping concentration, the spectral weight of the optical conductivity suppressed strongly in underdoped region increases quickly, and the peak position of the mid-infrared band moves towards to the lower energy region, then incorporates into the narrow band centered in zero energy in the heavily overdoped region. [ABSTRACT FROM AUTHOR]

The recently discovered charge order is an intrinsic and universal property of cuprate superconductors, however, its microscopic origin remains debated. Here we review briefly the theoretical work about the nature of charge order in cuprate superconductors. In particular, we show that the electron self-energy obliterates the electron Fermi surface around the antinodal region, leaving behind disconnected Fermi arcs located around the nodal region. The charge-order state on the other hand is driven by the Fermi-arc instability, with a characteristic wavevector corresponding to the hot spots of the Fermi arcs rather than the antinodal nesting vector. Since the pseudogap emanates from the electron self-energy, the Fermi arc, charge order, and pseudogap in cuprate superconductors are intimately related each other. [ABSTRACT FROM AUTHOR]

Based on the renormalized Hubbard model, the doping dependence of electron spectrum in cuprate superconductors is discussed within the self-consistent mean field theory. It is shown that the renormalization factor (then the quasiparticle coherent weight) increases almost linearly with the doping and plays an important role in the unconventional superconductivity for cuprate superconductors. It suppresses the magnitude of the quasiparticle peak in the electron spectrum, especially in underdoped region. By calculation of the energy and doping dependence of the electron spectral function, the main features of the electron spectrum in cuprate superconductors can be described qualitatively. In particular, with the increasing doping concentration, the position of the quasiparticle peak moves to the Fermi energy and the magnitude of the quasiparticle peak increases monotonically. Our results also show that the superconducting order parameter is determined by product of the renormalization factor and the pseudogap. [ABSTRACT FROM AUTHOR]

A long-standing unsolved problem is how a microscopic theory of superconductivity in cuprate superconductors based on the charge-spin separation can produce a large electron Fermi surface (EFS). Within the framework of the kinetic-energy driven superconducting mechanism, a full charge-spin recombination scheme is developed to fully recombine a charge carrier and a localized spin into an electron, and then is employed to study the electron-momentum distribution in cuprate superconductors. In particular, the theory shows that the underlying EFS fulfills Luttinger's theorem, and the sum rule for the constrained electron is obeyed. [ABSTRACT FROM AUTHOR]

In this paper, the high-energy magnetic excitations in cuprate superconductors are studied based on the kinetic energy driven superconducting mechanism. The spin self-energy is evaluated explicitly in terms of the collective charge carrier modes in the particle-hole and particle-particle channels, and employed to calculate the dynamical spin structure factor. Our results show the existence of damped but well-defined dispersive spin excitations in the whole doping phase diagram. In particular, the charge carrier doping has a more modest effect on the high-energy spin excitations, and then the high-energy magnetic excitations retain roughly constant energy as a function of doping, with spectral weights and dispersion relations comparable to those found in the parent compound. [ABSTRACT FROM AUTHOR]

Superconductivity in cuprate superconductors occurs upon charge-carrier doping Mott insulators, where a central question is what mechanism causes the loss of electrical resistance below the superconducting (SC) transition temperature? In this paper, we attempt to summarize the basic idea of the kinetic-energy-driven SC mechanism in the description of superconductivity in cuprate superconductors. The mechanism of the kinetic-energy-driven superconductivity is purely electronic without phonons, where the charge-carrier pairing interaction in the particle-particle channel arises directly from the kinetic energy by the exchange of spin excitations in the higher powers of the doping concentration. This kinetic-energy-driven d-wave SC-state is controlled by both the SC gap and quasiparticle coherence, which leads to that the maximal SC transition temperature occurs around the optimal doping, and then decreases in both the underdoped and overdoped regimes. In particular, the same charge-carrier interaction mediated by spin excitations that induces the SC-state in the particle-particle channel also generates the normal-state pseudogap state in the particle-hole channel. The normal-state pseudogap crossover temperature is much larger than the SC transition temperature in the underdoped and optimally doped regimes, and then monotonically decreases upon the increase of doping, eventually disappearing together with superconductivity at the end of the SC dome. This kinetic-energy-driven SC mechanism also indicates that the strong electron correlation favors superconductivity, since the main ingredient is identified into a charge-carrier pairing mechanism not from the external degree of freedom such as the phonon but rather solely from the internal spin degree of freedom of the electron. The typical properties of cuprate superconductors discussed within the framework of the kinetic-energy-driven SC mechanism are also reviewed. [ABSTRACT FROM AUTHOR]

Within the kinetic energy driven superconducting mechanism, the doping and temperature dependence of the superfluid density in cuprate superconductors is studied throughout the superconducting dome. It is shown that the superfluid density shows a crossover from the linear temperature dependence at low temperatures to a nonlinear one in the extremely low temperatures. In analogy to the dome-like shape of the doping dependent superconducting transition temperature, the maximal zero-temperature superfluid density occurs around the critical doping δ ≈ 0.195, and then decreases in both lower doped and higher doped regimes. [ABSTRACT FROM AUTHOR]