Spectral Function of Holes in a Quantum Antiferromagnet

Schmitt‐Rink, S.; Varma, C. M.; Ruckenstein, Andrei E.

doi:10.1103/physrevlett.60.2793

Cited by 536 publications

(455 citation statements)

References 14 publications

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“…In one picture, the single hole forms a coherent QP propagating in a medium of quantum-fluctuating spins, which strongly renormalizes the dispersion relations and the mutual interactions of the holes at finite doping. This spin-polaron picture is supported by numerical approaches, such as quantum Monte Carlo 4 , exact diagonalization 5 and self-consistent Born approximation (SCBA) 2 . In a contrasting picture, the notion of QP can break down due to various mechanism such as orthogonality catastrophe 6 , spin-charge separation 7 and/or localization effects 8 , reflecting the unconventional nature of two-dimensional (2D), strongly interacting fermions.…”

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confidence: 96%

“…T he dynamics of a single hole doped into a low-dimensional quantum antiferromagnet (AF) constitutes one of the classic unsolved problems, which has drawn much interest in the context of cuprate high-temperature superconductors [1][2][3] . In one picture, the single hole forms a coherent QP propagating in a medium of quantum-fluctuating spins, which strongly renormalizes the dispersion relations and the mutual interactions of the holes at finite doping.…”

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confidence: 99%

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Excitonic quasiparticles in a spin–orbit Mott insulator

et al. 2014

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In condensed matter systems, out of a large number of interacting degrees of freedom emerge weakly coupled quasiparticles (QPs), in terms of which most physical properties are described. The lack of identification of such QPs is a major barrier for understanding myriad exotic properties of correlated electrons, such as unconventional superconductivity and non-Fermi liquid behaviours. Here we report the observation of a composite particle in a quasi-two-dimensional spin-1/2 antiferromagnet Sr 2 IrO 4 -an exciton dressed with magnons-that propagates with the canonical characteristics of a QP: a finite QP residue and a lifetime longer than the hopping time scale. The dynamics of this charge-neutral excitation mirrors the fundamental process of the analogous one-hole propagation in the background of spins-1/2, and reveals the same intrinsic dynamics that is obscured for a single, charged-hole doped into two-dimensional cuprates.

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Excitonic quasiparticles in a spin–orbit Mott insulator

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“…Then the e ective interaction in the singlet channel sums the polarization bubbles connected by Coulomb interactions. Using (228) for the polarization bubble, it is shown [14] that for small momentum transfer the interaction in the Fig. 67.…”

Section: Interactions In Disordered Electronsmentioning

confidence: 99%

“…44 In Section 4.8, we have sketched the di culties of connecting to the same problem in one dimension when the ground state at zero doping is an antiferromagnet. In fact, analytic [228] and numerical [172] answers to the question for a single hole show the spectral weight of a heavy particle with an incoherent part composed of multiple spin-wave polaronic cloud. Simply extrapolated (a dangerous thing to do), a Fermi liquid is expected.…”

Section: The Doped Hubbard Modelmentioning

confidence: 99%

Singular or non-Fermi liquids

2002

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“…The introduction of nearest neighbour repulsion in the extended Hubbard model [8] emphasizes the relevance of charge degrees of freedom. In the l-J models and RVB theories the low energy sector of the problem is dominated by the spin degrees of freedom [9,10].…”

Section: Lntroductioamentioning

confidence: 99%

Density of states in high-Tc superconductors

Vettoor

Nandakumaran

1992

Physica C: Superconductivity

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The density of staleS and the low temperature specific heat of higb-Tc superconductors are calculated in a functional i n.formali$m using the slave boson technique. The manybody calculation in a saddle point approximation shows that the Iowener&Y sector is dominated by 3 single band. The calculated values of density of states are in cood apeemcot witb experimental results. 1.lntroductioaHigh temperature superronductivity in ceramic oxides raises serious questions regarding the mech~ anism of normal and superconducting state properties of these systems. Ever since the discovery [1), various theoretical models have been suggested and different mechanisms ranging from conventional weak coupling BCS-like to novel strong coupling formulations have been proposed (2-4). But still there is no general consensus on the relevant parameter regime and the mechanism of superconductivity in these systems.It is believed that the essential physics of nonnal and superconducting states reside in the Cu-O planar subsystem which is common to the copper oxide superconductors.Many theoretical models begin with a two-dimensional extended Hubbard model or Anderson lattice model with a strong on-site repulsive interaction [5-7}. The introduction of nearest neighbour repulsion in the extended Hubbard model [8] emphasizes the relevance of charge degrees of freedom. In the l-J models and RVB theories the low energy sector of the problem is dominated by the spin degrees of freedom [9,10].In this paper we analyze the extended model without nearest neighbour repulsion, but with a direct oxygen-oxygen hopping between the Po orbitals which brings to the scene, in addition to the spin degrees of freedom, the charge degrees of freedom.These models have been previously studied usin&a< mean field scheme [11,12]. We studied this stroaIlt ~ correlated problem using a slave boSOD (13) lem. At half filling, the materials are antifef'l'ODtit netically spin ordered insulators. The proximity. being a magnetic insulator makes strong corrdatiol relevant to the doped case.. Here we consider a model, in which the on-site .. pulsion imposes a double occupancy constraint., the copper 3d;cl_y2 orbital. We study tbis using a JaJp N expansion technique which is nonperturbative it the CQupling constants. The study is restricted to the mean field theory (N = 00 ). The partition f\mct\on and the free energy are derived in section 2. The expressions for the specific heat and the density of states have been derived in section 3. The numerical computations are presented in section 4. The co.clusions concerning the re normalized energy bands and the comparison with experiments are also discussed in section 4. The modelThe model we consider in this paper has three essential bands. As a consequence of the oxygen ligand enviYonment the copper 3d degeneracy is lifted and 0921-4534/92/$05.00

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Spectral Function of Holes in a Quantum Antiferromagnet

Cited by 536 publications

References 14 publications

Excitonic quasiparticles in a spin–orbit Mott insulator

Excitonic quasiparticles in a spin–orbit Mott insulator

Singular or non-Fermi liquids

Density of states in high-Tc superconductors

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