Anderson localization effects on the doped Hubbard model

Giovanni, Nathan; Civelli, Marcello; Aguiar, M. C. O.

doi:10.1103/physrevb.103.245134

Cited by 5 publications

(3 citation statements)

References 30 publications

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“…Usually, this is ascribed to intrinsic effects, in which pairing correlations diminish with doping, due to screening of local Coulomb interactions [19], but some authours have also addressed the role of disorder in surpressing superconductivity [20][21][22]. Disorder, however, is usually incorporated as random on-site energies in Hubbardlike models that can lead to Anderson localization phenomena [23][24][25], thus it is important to extend this effects to include also the possiblity of severe structural disorder within finite regions of the crystal.…”

Section: Introductionmentioning

confidence: 99%

Disorder-induced finite center-of-mass momentum Cooper pairing and its consequences to the critical temperature and superconducting gap of overdoped cuprates

Velasco¹,

Neto²

2023

Preprint

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One of the most studied classes of unconventional high-temperature superconductors is the hole-doped cuprates, where special attention is given to those doped with extra interstitial oxygens. In this context, the formation of spatially inhomogeneous agglomerates of dopant oxygen atoms in the form of nanosized puddles is not only relevant, but also subject of intense recent experimental and theoretical surveys. Following these efforts, in this work we show the consequences of the presence of networks of oxygen puddles in the superconducting state of overdoped cuprates. Starting from the inhomogeneous disordered background brought by the network of puddles, we show that an effective interaction between electrons can be mediated by the local vibrational degrees of freedom of each puddle, but the pairs arising from this interaction have a finite center-of-mass momentum p, thus breaking up the Cooper channel. Furthermore, we derive an analytical expression for the amplitude of the superconducting gap ∆ k in terms of disorder and finite center-of-mass momentum and show that amplitude fluctuations are induced in the superconducting state by the presence of the puddles, where both the gap and the critical temperature are affect and reduced by disorder and finite momentum pairs. Finally, we discuss our findings in the context of networks of superconducting oxygen nano-puddles in cuprates.

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Section: Introductionmentioning

confidence: 99%

Disorder-induced finite center-of-mass momentum Cooper pairing and its consequences to the critical temperature and superconducting gap of overdoped cuprates

Velasco¹,

Neto²

2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Usually, this is ascribed to intrinsic effects, in which pairing correlations diminish with doping, due to screening of local Coulomb interactions [19], but some authors have also addressed the role of disorder in suppressing superconductivity [20][21][22]. Disorder, however, is usually incorporated as random on-site energies in Hubbard-like models that can lead to Anderson localization phenomena [23][24][25], thus it is important to extend these effects to include also the possibility of severe structural disorder within finite regions of the crystal.…”

Section: Introductionmentioning

confidence: 99%

Gap fluctuations, Cooper pairs with finite center-of-mass momentum, and suppression of superconductivity in inhomogeneous systems with dopant superpuddles agglomerates

Velasco

Neto

2023

J. Phys.: Condens. Matter

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Spatially extended aggregates or clusters of dopants are ubiquitous in a plethora of granular superconducting systems, such as Al-doped MgB2 and N-dopedn Mo2N, forming a droplet network that is very important to their characterization and to the description of their superconducting properties.} At the same time, one of the most studied classes of unconventional superconducting materials are the high-temperature superconductors, where special attention is given to the hole-doped cuprates, where the carrier concentration is controlled by the amount of extra interstitial oxygen dopants. In this context, the formation of spatially inhomogeneous aggregates of interstitial dopant oxygen atoms, in the form of nanosized superpuddles, is not only relevant, but also a subject of intense recent experimental and theoretical surveys. Following these efforts, in this work we investigate the consequences of the presence of networks of {inhomogeneously distributed dopant} superpuddles on the superconducting state. Starting from the inhomogeneous extended disordered background brought by the network of superpuddles, we demonstrate, with the aid of an effective interaction between electrons mediated by the local vibrational degrees of freedom of each puddle, that the Cooper pairs arising from an attractive interaction in an inhomogeneous medium have a finite center-of-mass momentum, p, that breaks up the Cooper channel. Furthermore, we derive an analytical expression for the amplitude of the superconducting gap, △ k , in terms of disorder and finite center-of-mass momentum and show that amplitude fluctuations are induced in the superconducting state by the presence of the superpuddles, where both the gap and the critical temperature are reduced by disorder and finite momentum pairs. Finally, we discuss our findings in the context of {synchronized networks of superconducting oxygen nano-puddles in cuprates and in other granular superconducting systems.

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“…In the half-filled AHM, we study how Anderson and Coulomb disorders might jointly contribute to the metal-insulator transition (MIT). In order to solve the problem, we employ the typical medium dynamical mean-field theory (TMT-DMFT) with geometrical and arithmetical averages over the disorder configurations, which is a successful method for the MIT on a disordered lattice [17][18][19][20][21][22][23][24][25]. By selecting appropriate decoupling schemes, we use the equation of motion technique as an impurity solver, which is a good option for a rapid and reliable solution [26,27].…”

Section: Introductionmentioning

confidence: 99%

Anderson localization in the Anderson–Hubbard model with site-dependent interactions

Nguyen

Hoang

2022

New J. Phys.

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We consider Anderson localization in the half-filled Anderson-Hubbard model in the presence of either random on-site interactions or spatially alternating interactions in the lattice. By using dynamical mean field theory with the equation of motion method as an impurity solver, we calculate the arithmetically and geometrically averaged local density of states and derive the equations determining the critical value for the phase transition between metallic, Anderson and Mott insulating phases. The nonmagnetic ground state phase diagrams are constructed numerically. We figure out that the presence of Coulomb disorder drives the system toward the Anderson localized phase that can occur even in the absence of Anderson structural disorder. For the spatially alternating interactions, we find that the metallic region is reduced and the Mott and Anderson insulator ones are enlarged with increasing interaction modulation. Our obtained results are relevant to current research in ultracold atoms in disordered optical lattices where metal-insulator transition can be observed experimentally by using ultracold atom techniques.

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Anderson localization effects on the doped Hubbard model

Cited by 5 publications

References 30 publications

Disorder-induced finite center-of-mass momentum Cooper pairing and its consequences to the critical temperature and superconducting gap of overdoped cuprates

Disorder-induced finite center-of-mass momentum Cooper pairing and its consequences to the critical temperature and superconducting gap of overdoped cuprates

Gap fluctuations, Cooper pairs with finite center-of-mass momentum, and suppression of superconductivity in inhomogeneous systems with dopant superpuddles agglomerates

Anderson localization in the Anderson–Hubbard model with site-dependent interactions

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