Effect of external pressure on the normal and superconducting properties of high‐ cuprates

Сидоров, К. А.; Гавричков, В. А.; Николаев, С. В.; Pchelkina, Z. V.; Овчинников, С. Г.

doi:10.1002/pssb.201552465

Cited by 6 publications

(3 citation statements)

References 52 publications

(76 reference statements)

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“…The exchange interaction constants J x 01 and J y 01 which determine the value of the pairing interaction in the approach used are close to the values obtained from experiments on inelastic neutron scattering in cuprates [62] and from calculations that take into account the complete basis of quasiparticle cluster excitations [63] (J = 0.149 eV). To check whether the effect of the s * -wave component increasing remains at lower exchange interaction constants its dependence on doping in the x range from 0.21 to 0.27 was calculated with artificially reduced J (Fig.…”

Section: The Concentration and Temperature Dependences Of D-and Exten...supporting

confidence: 73%

The enhanced s*-wave component of the superconducting gap in the overdoped HTSC cuprates with orthorhombic distortion

Makarov,

Ovchinnikov

2021

Preprint

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In this work, the concentration and temperature dependences of the superconducting gap of the HTSC cuprate in the orthorhombic phase are obtained within the framework of the Hubbard model taking into account the exchange mechanism of pairing. The enhanced s * -wave component of the superconducting gap against the background of the prevailing d-wave component in a narrow range of hole concentrations in the overdoped region is found. To elucidate the reasons for such unusual behavior the electronic structure of the low-energy excitations and the structure of the contributions of the pair states to the superconducting gap in momentum space were investigated at different doping. It is shown that the presence of a shallow pocket in the region of the maximum value of the s * -wave component of the gap results in different symmetry of the superconducting gap in different regions of the k-space and an increase in the s * -wave component.

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Section: The Concentration and Temperature Dependences Of D-and Exten...supporting

confidence: 73%

The enhanced s*-wave component of the superconducting gap in the overdoped HTSC cuprates with orthorhombic distortion

Makarov,

Ovchinnikov

2021

Preprint

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“…provide input for calculations of the Fermi surface topology under HP, that has been suspected to determine some of the CDW features [5]. However, the existing electronic structure calculations report significant changes in the Fermi surface only for compressions much higher than the ones corresponding to the suppression of the CDWrelated anomalies reported here [42,43]. Changes in the Fermi-arc electronic structures at pressures as modest as those used here to suppress the CDW are therefore expected to be marginal.…”

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confidence: 95%

Rapid suppression of the charge density wave in YBa2Cu3O6.6 under hydrostatic pressure

et al. 2018

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We report on the effects of hydrostatic pressure (HP) on the charge density wave observed in underdoped cuprates. We studied YBa2Cu3O6.6 (Tc=61 K) using high-resolution inelastic x-ray scattering (IXS), and reveal an extreme sensitivity of the phonon anomalies related to the charge density wave (CDW) order to HP. The amplitudes of the normal state broadening and superconductivity induced phonon softening at QCDW rapidly decrease as HP is applied, resulting in the complete suppression of signatures of the CDW below ∼1 GPa. Additional IXS measurements on YBa2Cu3O6.75 demonstrate that this very rapid effect cannot be explained by pressure-induced modification of the doping level and highlight the different role of external pressure and doping in tuning the phase diagram of the cuprates. Our results provide new insights into the mechanisms underlying the CDW formation and its interplay with superconductivity.The complex phase diagrams of correlated electron systems are shaped by the interplay between almost degenerate electronic states. In the high-T c superconducting cuprates, charge density wave (CDW) modulations have been ubiquitously observed, appearing as a generic feature of the moderately doped CuO 2 plane [1-3, 5-10]. While the doping and magnetic field dependence of the CDW order and its competition with superconductivity have been thoroughly studied [2-4, 11, 12], the actual impact of CDW on the superconducting properties remains unclear. Recent studies of stripe ordered La 1.875 Ba 0.125 CuO 4 showed that the application of pressure increases T c , while drastically suppressing static spin and charge orders, as well as the local tilts of the CuO 6 octahedra which act as stripe pinning centers [13,14]. However, no direct measurements of the effect of pressure on the CDW in the other families of cuprates have been reported to date.High pressures have been extensively used as a tuning parameter of the superconducting properties of the cuprates, and yielded the highest T c ever reported in these materials [15,16] (and that held the world record until very recently, when it got surpassed by highly pressurized H 3 S [17]). In YBa 2 Cu 3 O 6+x , the few available structural studies revealed that hydrostatic pressure (HP) brings the superconducting CuO 2 planes and the Cu-O chains closer together, leading to a net increase of the number of holes per Cu atom in the CuO 2 planes [18]. Recently it was shown that HP up to ∼ 30 GPa applied on fully oxygenated YBa 2 Cu 3 O 7 , provides access to the so-far unreachable highly overdoped and non-superconducting phase of this material [19]. On the other hand, in the underdoped region of the phase diagram and particularly in the region of the T c vs doping plateau where the CDW is best developed, a large increase of T c is observed under HP, yielding T c largely exceeding that of the optimally doped compound. The effective HP dependence of T c reflects the combination of pressure-induced doping with other HP effects, on e.g. superexchange interactions, or oxygen ordering [20...

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“…Due to the strong correlations at the Cu-sites, the one-band Hubbard model has been largely used to describe such systems, leading to results which are important for elucidate the mechanisms of superconductivity in cuprates [4,5,[12][13][14][15]. Nevertheless, the fact that the oxygen sites may be occupied by holes when the system is doped suggests that a model which also takes into account the oxygen can be more adequate to treat the doped regime of such systems [16][17][18][19][20][21]. In this sort of model, the hybridization between the d orbitals of the cooper and the p orbitals of the oxygen becomes an important parameter which is sensitive to changes of external pressure [22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Effects of a k⃗-dependent Hybridisation on the Fermi surface of an extended d–p Hubbard model

Lalis¹,

Calegari

Prauchner³

et al. 2020

Philosophical Magazine

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The topology of the Fermi surface of an extended d−p Hubbard model is investigated using the Green's function technique in a n-pole approximation. The effects of the d − p hybridization on the Fermi surface are the main focus in the present work. Nevertheless, the effects of doping, Coulomb interaction and hopping to secondnearest-neighbors on the Fermi surface, are also studied. Particularly, it is shown that the crossover from hole-like to electron-like Fermi surface (Lifshitz transition) is deeply affected by the d − p hybridization. Moreover, the pseudogap present in the low doping regime is also affected by the hybridization. The results show that both the doping and the hybridization act in the sense of suppresses the pseudogap. Therefore, the systematic investigation of the Fermi surface topology, shows that not only the doping but also the hybridization can be considered as a control parameter for both the pseudogap and the Lifshitz transition. Assuming that the hybridization is sensitive to external pressure, the present results agree qualitatively with recent experimental data for the cuprate Nd-LSCO.

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Effect of external pressure on the normal and superconducting properties of high‐ cuprates

Cited by 6 publications

References 52 publications

The enhanced s*-wave component of the superconducting gap in the overdoped HTSC cuprates with orthorhombic distortion

The enhanced s*-wave component of the superconducting gap in the overdoped HTSC cuprates with orthorhombic distortion

Rapid suppression of the charge density wave in YBa2Cu3O6.6 under hydrostatic pressure

Effects of a k⃗-dependent Hybridisation on the Fermi surface of an extended d–p Hubbard model

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