Phase Diagram Of Hole-doped Cuprates Research Articles

Doping dependence of scattering rate for linear-in-temperature resistivity in cuprate superconductors

The origin of the linear-in-temperature (T-linear) resistivity in cuprate superconductors remains a profound mystery in condensed matter physics. Here, we investigate the dependence of the T-linear resistivity coefficient on doping, i.e., A1(p), for three typical regions in the temperature versus doping phase diagram of hole-doped cuprates, from which the doping dependence of the scattering rate, i.e., α1(p), is further derived. It is found that for region I (p<p* and T>T*), α1(p) is almost a constant; for region II (p>p* and T>Tcoh), α1(p)∝p; for region III (p>p* and T<Tcoh), α1(p)∝p(pc−p), where T* is the onset temperature of the pseudogap phase, p* indicates the doping at which T* goes to zero, Tcoh marks the onset of antinodal quasiparticle coherence, and pc is the doping where the low-temperature linear behavior in the overdoped regime vanishes. Moreover, the deduced α1(p) relations are verified with the experimental data from previous reports. The discovered scattering rate versus doping relationship will shed light on the scattering mechanism underlying the T-linear resistivity in cuprate superconductors. Published by the American Physical Society 2024

Superfluid density and two-component conductivity in hole-doped cuprates

While the pseudogap dominates the phase diagram of hole-doped cuprates, connecting the antiferromagnetic parent insulator at low doping to the strange metal at higher doping, its origin and relation to superconductivity remains unknown. In order to proceed, a complete understanding of how the single hole–initially localized in the Mott state–becomes mobile and ultimately evolves into a coherent quasiparticle at the end of the superconducting dome is required. In order to affect this development, we examine recent transport and spectroscopic studies of hole-doped cuprates across their phase diagram. In the process, we highlight a set of empirical correlations between the superfluid density and certain normal state properties of hole-doped cuprates that offer fresh insights into the emergence of metallicity within the CuO2 plane and its influence on the robustness of the superconducting state. We conclude by arguing that the overall behavior is best understood in terms of two distinct current-carrying fluids, only one of which dominates the superconducting condensate and is gapped out below the pseudogap endpoint at a critical hole concentration p∗.

Analysis of optical data using extended Drude model and generalized Allen’s formulas

Extended Drude model formalism has been successfully utilized for analyzing optical spectra of strongly correlated electron systems including heavy-fermion systems and high-Tc superconducting iron pnictides and cuprates. Furthermore, generalized Allen’s formulas have been developed and applied to extract the electron-boson spectral density function from measured optical data of high temperature superconductors including cuprates in various material phases. Here we used a reverse process to obtain various optical quantities starting from two typical electron-boson spectral density model functions for three intriguing (normal, pseudogap, and d-wave superconducting) material phases in cuprates. We also assigned the calculated optical results to designated regions in the phase diagram of hole-doped cuprates and compared them with the corresponding measured optical spectra of Bi2Sr2CaCu2 (Bi-2212). This comparison suggested that this way of optical data analysis can be a convincing method to study correlated electrons in the copper oxide superconductors and other superconducting systems as well.

Theory of dual fermion superconductivity in hole-doped cuprates

Since the discovery of the cuprate high-temperature superconductivity in 1986, a universal phase diagram has been constructed experimentally and numerous theoretical models have been proposed. However, there remains no consensus on the underlying physics thus far. Here, we theoretically investigate the phase diagram of hole-doped cuprates based on an itinerant-localized dual fermion model, with the charge carriers doped on the oxygen sites and localized holes on the copper $d_{x^{2}-y^{2}}$ orbitals. We analytically demonstrate that the puzzling anomalous normal state or the strange metal could simply stem from a free Fermi gas of carriers bathing in copper antiferromagnetic spin fluctuations. The short-range high-energy spin excitations also act as the `magnetic glue' of carrier Cooper pairs and induce $d$-wave superconductivity from the underdoped to overdoped regime, distinctly diffrent from the conventional low-frequency magnetic fluctuation mechanism. We further sketch out the characteristic dome-shaped critical temperature $T_c$ versus doping level. The emergence of the pseudogap is ascribed to the localization of partial carriers coupled to the local copper moments or a crossover from the strange metal to a nodal Kondo-like insulator. Our work provides a consistent theoretical framework to understand the typical phase diagram of hole-doped cuprates and paves a distinct way to the studies of both non-Fermi liquid and unconventional superconductivity in strongly correlated systems.

Gutzwiller charge phase diagram of cuprates, including electron–phonon coupling effects

Besides significant electronic correlations, high-temperature superconductors also show a strong coupling of electrons to a number of lattice modes. Combined with the experimental detection of electronic inhomogeneities and ordering phenomena in many high-Tc compounds, these features raise the question as to what extent phonons are involved in the associated instabilities. Here we address this problem based on the Hubbard model including a coupling to phonons in order to capture several salient features of the phase diagram of hole-doped cuprates. Charge degrees of freedom, which are suppressed by the large Hubbard U near half-filling, are found to become active at a fairly low doping level. We find that possible charge order is mainly driven by Fermi surface nesting, with competition between a near- order at low doping and antinodal nesting at higher doping, very similar to the momentum structure of magnetic fluctuations. The resulting nesting vectors are generally consistent with photoemission and tunneling observations, evidence for charge density wave order in YBa2Cu3O including Kohn anomalies, and suggestions of competition between one- and two-q-vector nesting.

Spatial dichotomy of quasiparticle dynamics in underdoped thin-filmYBa2Cu3O7−δsuperconductors

By the spatial-temporal-resolved femtosecond spectroscopy on well-textured (110)- and (100)-YBCO thin films, two distinctly temperature-dependent characteristics of quasiparticle relaxation in the nodal and antinodal directions are clearly identified. One temperature dependence associated with a high-energy gap has been observed along the ab diagonal for the whole hole-doping region and along the $b$ axis except near optimal doping, while the other temperature dependence related to the opening of the superconducting gap appears along $b$ axis regardless of the hole concentration. This spatial dichotomy between the nodal and antinodal quasiparticle dynamics and the evolution of gap symmetry with hole doping are discussed for enlightenment on the nature of the phase diagram of hole-doped cuprates. These strongly suggest that the two characteristics may have different physical origins and compete with each other.

Magnetization, Nernst effect and vorticity in the cuprates

Nernst and magnetization experiments reveal the existence of a large region of the cuprate phase diagram above the T c curve in which vorticity and weak diamagnetism exist without phase coherence. We discuss the implication that the transition at T c is caused by the loss of long-range phase coherence caused by spontaneous vortex creation. Below T c , these measurements provide an estimate of the depairing field H c 2 which is found to be very large ( 40 – 100 T depending on doping). We discuss the high-field Nernst and magnetization results, binding energy, and the phase diagram of hole-doped cuprates. Some new magnetization results on the vortex liquid in very underdoped LSCO in the limit T → 0 are reported as well.

Seven Energy/Temperature Scales in Hole-Doped Cuprates

The purpose of this paper is to discuss a phase diagram of hole-doped cuprates. Hole-doped cuprates have a very rich phase diagram as a function of doping. This is due to a charge inhomogeneity in CuO2 planes: the charge distribution in CuO2 planes is inhomogeneous both on a nanoscale and macroscale. Depending on the doping level, the CuO2 planes comprise at least four different types of clusters. Varying with doping level, the minimum size of these clusters is about a few nanometers, and their maximum size is macroscopic. Each type of clusters has its own features. As a consequence, the common phase diagram consists of, at least, seven different energy/temperature scales. As an example, we consider a phase diagram of Bi2Sr2CaCu2O8+x.

Two energy gaps in cuprates: pairing and coherent gaps. The interpretation of tunneling and inelastic neutron scattering measurements.

Tunneling and inelastic neutron scattering (INS) measurements in cuprates are discussed. There is a clear discrepancy among energy-gap values for different 90 K cuprates, inferred from tunneling measurements. By using the phase diagram of hole-doped cuprates we interpret tunneling measurements in 90 K cuprates and INS data in YBCO.