scholarly journals Stripe order enhanced superconductivity in the Hubbard model

2021 ◽  
Vol 119 (1) ◽  
pp. e2109406119
Author(s):  
Hong-Chen Jiang ◽  
Steven A. Kivelson
Keyword(s):  
High Temperature ◽  
Hubbard Model ◽  
High Temperature Superconductivity ◽  
High Temperature Superconductors ◽  
Density Wave ◽  
Long Distance ◽  
Positive Role ◽  
Density Matrix Renormalization ◽  
Period 2 ◽  
Stripe Order

Unidirectional (“stripe”) charge density wave order has now been established as a ubiquitous feature in the phase diagram of the cuprate high-temperature superconductors, where it generally competes with superconductivity. Nonetheless, on theoretical grounds it has been conjectured that stripe order (or other forms of “optimal” inhomogeneity) may play an essential positive role in the mechanism of high-temperature superconductivity. Here, we report density matrix renormalization group studies of the Hubbard model on long four- and six-leg cylinders, where the hopping matrix elements transverse to the long direction are periodically modulated—mimicking the effect of putative period 2 stripe order. We find that even modest amplitude modulations can enhance the long-distance superconducting correlations by many orders of magnitude and drive the system into a phase with a substantial spin gap and superconducting quasi–long-range order with a Luttinger exponent, Ksc∼1.

SOFT-PLASMON MECHANISM FOR HIGH-TEMPERATURE SUPERCONDUCTIVITY

1987 ◽  
Vol 01 (03n04) ◽  
pp. 965-971 ◽  
Author(s):  
J. ASHKENAZI ◽  
C.G. KUPER ◽  
R. TYK
Keyword(s):  
High Temperature ◽  
Charge Density ◽  
Charge Density Wave ◽  
High Temperature Superconductivity ◽  
High Temperature Superconductors ◽  
Density Wave ◽  
Cooper Pairs ◽  
Strong Electron ◽  
Metal Insulator ◽  
Order Of Magnitude

Recently-discovered high-temperature superconductors border on a Mott metal insulator transition; pure La2CuO4 undergoes a commensurate charge-density-wave transition and becomes an insulator. At other compositions, the incipient charge-density wave causes a drastic softening of those plasmon modes with wave vectors connecting points on the Fermi surface. These soft plasmons (typically tenths of an electron-volt) serve as the attraction which binds Cooper pairs, instead of the usual phonons. Consequently, transition temperatures are an order of magnitude larger than for phonon-induced superconductivity. One of the factors responsible for the strong electron - plasmon coupling is the influence of the empty f-orbitals of La or Ba.

scholarly journals GLASS MODEL, HUBBARD MODEL AND HIGH-TEMPERATURE SUPERCONDUCTIVITY

1999 ◽  
Vol 10 (01) ◽  
pp. 309-320 ◽  
Author(s):  
INGO MORGENSTERN ◽  
WERNER FETTES ◽  
THOMAS HUSSLEIN ◽  
DENNIS M. NEWNS ◽  
PRATAP C. PATTNAIK
Keyword(s):  
High Temperature ◽  
Hubbard Model ◽  
High Temperature Superconductivity ◽  
High Temperature Superconductors ◽  
Finite Size ◽  
Microscopic Level ◽  
Finite Size Scaling ◽  
Microscopic Mechanism ◽  
Glass Model ◽  
Superconducting Correlations

In this paper we revisit the glass model describing the macroscopic behavior of the High-Temperature superconductors. We link the glass model at the microscopic level to the striped phase phenomenon, recently discussed widely. The size of the striped phase domains is consistent with earlier predictions of the glass model when it was introduced for High-Temperature Superconductivity in 1987. In an additional step we use the Hubbard model to describe the microscopic mechanism for d-wave pairing within these finite size stripes. We discuss the implications for superconducting correlations of the Hubbard model, which are much higher for stripes than for squares, for finite size scaling, and for the new view of the glass model picture.

scholarly journals Square Lattice Iridates

2019 ◽  
Vol 10 (1) ◽  
pp. 315-336 ◽  
Author(s):  
Joel Bertinshaw ◽  
Y.K. Kim ◽  
Giniyat Khaliullin ◽  
B.J. Kim
Keyword(s):  
High Temperature ◽  
High Temperature Superconductivity ◽  
High Temperature Superconductors ◽  
Single Layer ◽  
Square Lattice ◽  
Spin Orbit Coupling ◽  
Fermi Arcs ◽  
Firm Evidence ◽  
Energy Physics ◽  
Strong Spin

Over the past few years, Sr2IrO4, a single-layer member of the Ruddlesden–Popper series iridates, has received much attention as a close analog of cuprate high-temperature superconductors. Although there is not yet firm evidence for superconductivity, a remarkable range of cuprate phenomenology has been reproduced in electron- and hole-doped iridates including pseudogaps, Fermi arcs, and d-wave gaps. Furthermore, many symmetry-breaking orders reminiscent of those decorating the cuprate phase diagram have been reported using various experimental probes. We discuss how the electronic structures of Sr2IrO4 through strong spin-orbit coupling leads to the low-energy physics that had long been unique to cuprates, what the similarities and differences between cuprates and iridates are, and how these advance the field of high-temperature superconductivity by isolating essential ingredients of superconductivity from a rich array of phenomena that surround it. Finally, we comment on the prospect of finding a new high-temperature superconductor based on the iridate series.

Electron-Doped High Tc Superconductors

MRS Bulletin ◽  
1990 ◽  
Vol 15 (6) ◽  
pp. 60-67 ◽  
Author(s):  
M. Brian Maple
Keyword(s):  
High Temperature ◽  
High Temperature Superconductivity ◽  
High Temperature Superconductors ◽  
Building Blocks ◽  
The United States ◽  
Charge Carriers ◽  
Critical Temperatures ◽  
High Tc ◽  
Prevailing View ◽  
Identical Crystal

Since the discovery of high temperature superconductivity in layered copper-oxide compounds in the latter part of 1986, an enormous amount of research has been carried out on these remarkable materials. Prior to 1989, the prevailing view was that the charge carriers responsible for superconductivity in these materials were holes that move through conducting CuO2 planes. The CuO2 planes are the basic building blocks of the crystal structures of all the presently known oxides with superconducting critical temperatures Tc greater than ~30 K. Recently, new superconducting materials have been discovered in Japan and the United States in which the charge carriers involved in the superconductivity appear to be electrons, rather than holes, that reside within the conducting CuO2 planes. These findings could have important implications regarding viable theories of high temperature superconductivity as well as strategies for finding new high temperature superconductors.The new electron-doped materials have the chemical formula Ln2-xMxCuO4-y and exhibit superconductivity with superconducting critical temperatures Tc as high as ~25 K for x ≍ 0.15 and y ≍ 0.02. Superconductivity has been discovered for M = Ce and Ln = Pr, Nd, Sm, and Eu, and for M = Th and Ln = Pr, Nd, and Sm. A related compound with the identical crystal structure, Nd2CuO4-x-y Fx, has also been found to display superconductivity withTc ≍ 25 K. Recently, it has been observed that superconductivity with Tc ≍ 25 K can even be induced in nonsuperconducting Nd2-xCexCuO4-y compounds by substituting Ga or In for Cu. Thus, it appears that the CuO2 planes can be doped with electrons, rendering the Ln2CuO4-y parent compounds metallic and superconducting, by substituting electron donor elements at sites within, as well as outside, the CuO2 planes; i.e., by substituting (1) Ce4+ or Th4+ ions for Ln3+ ions; (2) F1- ions for O2- ions; and (3) Ga3+ or In3+ ions for Cu2+ ions.

EFFECTIVE THEORY FOR HIGH-TEMPERATURE SUPERCONDUCTIVITY BASED ON DUALITY AT S = 1/2 ANTIFERROMAGNETIC HEISENBERG MODEL

2005 ◽  
Vol 19 (12) ◽  
pp. 571-579 ◽  
Author(s):  
TAKAO MORINARI
Keyword(s):  
High Temperature ◽  
Heisenberg Model ◽  
High Temperature Superconductivity ◽  
High Temperature Superconductors ◽  
Parent Compound ◽  
High Energy ◽  
Field Application ◽  
Effective Theory ◽  
Dirac Fermions ◽  
Antiferromagnetic Heisenberg Model

It is argued that in two-dimension duality connects the CP1 representation of the S = 1/2 antiferromagnetic Heisenberg model with the Schwinger model in which Dirac fermions are interact via a U(1) gauge field. Application of this duality to underdoped high-temperature superconductors suggests that the high-energy fermionic excitation at the Mott insulating parent compound turns out to be a low-lying excitation in the spin disordered regime. A picture for high-temperature superconductivity is proposed.

Crystal Growth of High Temperature Superconductors

MRS Bulletin ◽  
1988 ◽  
Vol 13 (10) ◽  
pp. 56-61 ◽  
Author(s):  
H.J. Scheel ◽  
F. Licci
Keyword(s):  
High Temperature ◽  
Critical Current Density ◽  
Single Crystals ◽  
Critical Current ◽  
Current Density ◽  
Large Scale ◽  
High Temperature Superconductivity ◽  
High Temperature Superconductors ◽  
Superconducting Transition ◽  
Theoretical Understanding

The discovery of high temperature superconductivity (HTSC) in oxide compounds has confronted materials scientists with many challenging problems. These include the preparation of ceramic samples with critical current density of about 106 A/cm2 at 77 K and sufficient mechanical strength for large-scale electrotechnical and magnetic applications and the preparation of epitaxial thin films of high structural perfection for electronic devices.The main interest in the growth of single crystals is for the study of physical phenomena, which will help achieve a theoretical understanding of HTSC. Theorists still do not agree on the fundamental mechanisms of HTSC, and there is a need for good data on relatively defect-free materials in order to test the many models. In addition, the study of the role of defects like twins, grain boundaries, and dislocations in single crystals is important for understanding such parameters as the critical current density. The study of HTSC with single crystals is also expected to be helpful for finding optimum materials for the various applications and hopefully achieving higher values of the superconducting transition temperature Tc than the current maximum of about 125 K. It seems unlikely at present that single crystals will be used in commercial devices, but this possibility cannot be ruled out as crystal size and quality improve.

PAIRING STATE AND HIGH TEMPERATURE SUPERCONDUCTIVITY OF SEMI-LOCALIZED 2D ELECTRON SYSTEM WITH CIRCULAR MOLECULAR ORBITS

2002 ◽  
Vol 16 (10n11) ◽  
pp. 351-362 ◽  
Author(s):  
MASANORI SUGAHARA ◽  
NIKOLAI N. BOGOLUBOV
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Upper Bound ◽  
High Temperature Superconductivity ◽  
High Temperature Superconductors ◽  
Electron System ◽  
Circular Orbits ◽  
New Model ◽  
Pairing State ◽  
The Stability

Recently, new types of high temperature superconductors have been found which are characterized by the existence of circular molecular orbits in each unit site of 2D s/p electron system. In view of the characteristic, a new model of superconductivity is studied based on the stability of the correlated state of electrons in the 2D interconnection of circular orbits. This model gives an estimation of the upper bound of superfluidity transition temperature: T c ~ 130-400 K for fcc C 60, and T c ~ 110-340 K for hole-doped MgB 2.

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