Symmetry of binding in doped antiferromagnets

Wróbel, P.; Eder, R.

doi:10.1103/physrevb.58.15160

Cited by 30 publications

(57 citation statements)

References 29 publications

(46 reference statements)

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“…Note that this trend is consistent with the prediction from the spin polaron picture. 9,10,18 While at JϾ0.3t the p (,) and p (,0) states are clearly excited states, the energy levels look quite complicated in the range 0.2tрJр0.3t. Note that the d, p (,) and p (,0) states are almost degenerate at Jϭ0.3t, although the d state is still the ground state.…”

Section: Low-lying States With Different Symmetriesmentioning

confidence: 99%

“…Later it was shown that such pairing of holes at ͱ2 arises naturally if the wave function has d x 2 Ϫy 2 symmetry. 8,9 But in order to firmly establish the role of d-wave hole pairing in the theory of superconductivity, one has to understand how strong and robust the pairing is. In fact a numerical study 7 has shown that the binding energy of the d channel is negative but small and that the holes may not be tightly bound in real space.…”

Section: Introductionmentioning

confidence: 99%

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Low-energy states with different symmetries in thet−Jmodel with two holes on a 32-site lattice

Leung

2002

Phys. Rev. B

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We study the low-energy states of the t-J model with two holes on a 32-site lattice with periodic boundary conditions. In contrary to common belief, we find that the state with d x 2 Ϫy 2 symmetry is not always the ground state in the realistic parameter range 0.2рJ/tр0.4. There exist low-lying finite-momentum p states whose energies are lower than the d x 2 Ϫy 2 state when J/t is small enough. We compare various properties of these low-energy states at J/tϭ0.3 where they are almost degenerate and find that those properties associated with the holes ͑such as the hole-hole correlation and the electron momentum distribution function͒ are very different between the d x 2 Ϫy 2 and p states, while their spin properties are very similar. Finally, we demonstrate that by adding ''realistic'' terms to the t-J model Hamiltonian, we can easily destroy the d x 2 Ϫy 2 ground state. This casts doubt on the robustness of the d x 2 Ϫy 2 state as the ground state in a microscopic model for the hightemperature superconductors.

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Section: Low-lying States With Different Symmetriesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Low-energy states with different symmetries in thet−Jmodel with two holes on a 32-site lattice

Leung

2002

Phys. Rev. B

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“…10͑c͒. variational study of the t-J model, a similar effect has been observed in the context of the caterpillarlike movement of holes. 25 A rigorous account for the retardation yields modified equations for the bound-state energies, leaving the qualitative picture drawn in the static limit essentially unchanged:…”

Section: ͑43͒mentioning

confidence: 99%

“…Qualitatively similar questions have been addressed in a recent variational study of the hole pairing in the t-J model. 25 Our numerical ED results for the t-J z model are obtained…”

Section: Introductionmentioning

confidence: 99%

Holes in thet−Jzmodel: A diagrammatic study

Chernyshev¹,

Leung²

1999

Phys. Rev. B

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The t-J z model is the strongly anisotropic limit of the t-J model which captures some general properties of doped antiferromagnets ͑AF's͒. The absence of spin fluctuations simplifies the analytical treatment of hole motion in an AF background, and allows us to calculate single-and two-hole spectra with a high accuracy using a regular diagram technique combined with a real-space approach. At the same time, numerical studies of this model via exact diagonalization on small clusters show negligible finite-size effects for a number of quantities, thus allowing a direct comparison between analytical and numerical results. Both approaches demonstrate that the holes have a tendency to pair in p-and d-wave channels at realistic values of t/J. Interactions leading to pairing and effects selecting p and d waves are thoroughly investigated. The role of transverse spin fluctuations is considered using perturbation theory. Based on the results of the present study, we discuss the pairing problem in the realistic t-J-like model. Possible implications for preformed pairs formation and phase separation are drawn. ͓S0163-1829͑99͒04127-2͔

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“…Despite the intensive work on this problem in the last 20 years, investigation of binding even within the single band models, like the t-J model, continued to represent a challenging task [2]. After extensive analytical as well as numerical efforts devoted to the two-hole problem in the t-J model [2][3][4][5][6][7][8], a general consensus has been established that the bound pair with a d-wave symmetry represents the ground state in a parameter range J/t 0.4. Nevertheless, in the regime J/t 1 the symmetry of the ground state crosses to p-wave, raising doubts of many authors about the relevance of the t-J model for high-T c superconductivity.…”

Section: Introductionmentioning

confidence: 99%

Two Holes in the t–J Model Form a Bound State for Any Nonzero J/t

Vidmar

Bonča

2013

J Supercond Nov Magn

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Determination of the parameter regime in which two holes in the t-J model form a bound state represents a long standing open problem in the field of strongly correlated systems. By applying and systematically improving the exact diagonalization method defined over a limited functional space (EDLFS), we show that the average distance between two holes scales as d ∼ 2(J/t) −1/4 for J/t < 0.15, therefore providing strong evidence that two holes in the t-J model form the bound state for any nonzero J/t. However, the symmetry of such bound pair in the ground state is p-wave. This state is consistent with phase separation at finite hole filling, as observed in a recent study [Maska et al, Phys. Rev. B 85, 245113 (2012)].

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Symmetry of binding in doped antiferromagnets

Cited by 30 publications

References 29 publications

Low-energy states with different symmetries in thet−Jmodel with two holes on a 32-site lattice

Low-energy states with different symmetries in thet−Jmodel with two holes on a 32-site lattice

Holes in thet−Jzmodel: A diagrammatic study

Two Holes in the t–J Model Form a Bound State for Any Nonzero J/t

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