Temperature Dependence of the Upper Critical Field in Disordered Hubbard Model with Attraction

Kuchinskiǐ, É. Z.; Kuleeva, N. A.; Sadovskiǐ, M. V.

doi:10.1134/s1063776117120159

Cited by 4 publications

(7 citation statements)

References 34 publications

(59 reference statements)

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“…For orbital critical magnetic field (cf. [28]) in the same model, for the same coupling strength and T → 0, for a characteristic value of lattice parameter a = 3.3 * 10 −8 cm, we obtain H c2 ≈ 1.6 * 10 8 Gauss. Thus, the orbital critical magnetic field at low temperatures increases with coupling strength much faster than paramagnetic field and in BEC limit the main contribution to the upper critical magnetic field at low temperatures will be due to paramagnetic effect.…”

Section: Temperature Dependence Of Paramagnetic Critical Fieldsupporting

confidence: 51%

“…Let us consider disorder influence on the temperature dependence of the upper critical field H c2 (T ) in a wide region of attraction strength U , including the BCS -BEC crossover region, as well as for the wide interval of disorders, up to the vicinity of Anderson transition [28]. In Nozieres -Schmitt-Rink approach used here the critical temperature of superconducting transition is determined by a joint solution of equation for Cooper instability in Cooper particle -particle channel in weak coupling approximation and equation for the chemical potential of the system, which is defined for the whole interval of the values of Hubbard interaction from the condition of quarter -filling of the band within DMFT+Σ approximation.…”

Section: Temperature Dependence Of the Orbital Upper Critical Fieldmentioning

confidence: 99%

“…We shall also review the closely related results of Refs. [28,29] on the temperature dependence of orbital and paramagnetic upper critical magnetic fields in the region of this crossover and for different levels of disordering.…”

Section: Introductionmentioning

confidence: 97%

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Ginzburg-Landau expansion and the upper critical field in disordered attractive Hubbard model

Kuleeva,

Kuchinskii,

Sadovskii

2020

Preprint

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We present a short review of our studies of disorder influence upon Ginzburg -Landau expansion coefficients in Anderson -Hubbard model with attraction in the framework of the generalized DMFT+Σ approximation. A wide range of attractive potentials U is considered -from weak coupling limit, where superconductivity is described by BCS model, to the limit of very strong coupling, where superconducting transition is related to Bose -Einstein condensation (BEC) of compact Cooper pairs, which are formed at temperatures significantly higher than the temperature of superconducting transition, as well as the wide range of disorders -from weak to strong, when the system is in the vicinity of Anderson transition. For the same range of parameters we study in detail the temperature behavior of orbital and paramagnetic upper critical field Hc2(T ), which demonstrates the anomalies both due to the growth of attractive potential and the effects of strong disordering.

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Section: Temperature Dependence Of Paramagnetic Critical Fieldsupporting

confidence: 51%

Section: Temperature Dependence Of the Orbital Upper Critical Fieldmentioning

confidence: 99%

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Ginzburg-Landau expansion and the upper critical field in disordered attractive Hubbard model

Kuleeva,

Kuchinskii,

Sadovskii

2020

Preprint

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“…To introduce the effect of magnetic field H, we only have to replace the condition for divergence of the uniform superconducting susceptibility [Eq. ( 2)] with that for divergence of a finitemomentum superconducting susceptibility [27]…”

Section: Pair-formation Vortex-liquid-formation and Vortex-lattice-fo...mentioning

confidence: 99%

Stabilization of the vortex-liquid state by strong pairing interaction

Adachi

Ikeda

2019

Phys. Rev. B

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We theoretically investigate qualitative features of the field-temperature (H-T ) phase diagram of superconductors with strong attractive interaction lying in the BCS-BEC crossover regime. Starting with a simple attractive Hubbard model, we estimate three kinds of characteristic fields, i.e., the pair-formation field H * , the vortex-liquid-formation field Hc2, and the vortex-lattice-formation field H melt . The region between Hc2 and H melt , as well as that between Hc2 and H * , is found to be enlarged as the interaction is stronger. In other words, a strong attractive interaction can stabilize both the vortex-liquid and preformed-pair regions. We also point out the expected particle-density dependence of the H-T phase diagram.

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“…A more general approach, described in Ref. [34], suggests that linear H c − T c relation in the wide temperature range can be observed for systems with strong pairing interaction. According to the phase diagram of SC in Cd 3 As 2 [15,17], the type of pairing potential (evenor odd-parity) depends not on the integral strength of ee attraction, but rather on the relation between intraand inter-orbital components.…”

mentioning

confidence: 99%

Observation of subkelvin superconductivity in Cd3As2 thin films

et al. 2019

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We report the first experimental observation of superconductivity in Cd3As2 thin films without application of external pressure. Surface studies suggest that the observed transport characteristics are related to the polycrystalline continuous part of investigated films with homogeneous distribution of elements and the Cd-to-As ratio close to stoichiometric Cd3As2. The latter is also supported by Raman spectra of the studied films, which are similar to those of Cd3As2 single crystals. The formation of superconducting phase in films under study is confirmed by the characteristic behavior of temperature and magnetic field dependence of samples resistances, as well as by the presence of pronounced zero-resistance plateaux in dV /dI characteristics. The corresponding Hc−Tc plots reveal a clearly pronounced linear behavior within the intermediate temperature range, similar to that observed for bulk Cd3As2 and Bi2Se3 films under pressure, suggesting the possibility of nontrivial pairing in the films under investigation. We discuss a possible role of sample inhomogeneities and crystal strains in the observed phenomena.Weyl and Dirac semimetals (WSM and DSM) currently attract wide interest related to the existence of Dirac nodes in their electron spectrum and related nontrivial topological characteristics of both bulk and surface states [1][2][3]. A special attention is drawn to the Cd 3 As 2 compound, which proved to be air-stable, unlike some other DSM materials [4][5][6][7][8]. This compound is known and has been studied for quite a long time [9][10][11][12]. Nevertheless, it is still very popular since the Dirac nodes of this semimetal are protected by the crystal symmetry and the electron states exhibit interesting topological properties, such as spin-momentum locking. Due to the high symmetry, DSM materials can undergo transitions to other topological phases (e.g. WSM) as a result of breaking certain symmetries or applying some external factors.The existence of topologically protected electron states gives a new impetus to the problem of topological superconductivity (TSC) being discussed for a long time [13][14][15]. In particular, Refs. [16,17] provide a theoretical analysis of the possible types of SC pairing in the systems of Cd 3 As 2 type, including topologically nontrivial ones. Basically, the existence of nontrivial pairing potential (leading to the emergence of triplet Cooper pairs) should induce the formation of Majoranna modes at the surface of the crystal, which can be used in the faulttolerant quantum computing [14]. The SC phase emergence in Cd 3 As 2 was reported in Ref.[18], however, it was observed at pressures above the structural transition from the tetragonal to trigonal phase. While theoretical works suggest the stabilization of TSC phase upon such symmetry lowering [16,17], such transition also implies appearance of the gap at Dirac nodes, thus, suppressing the DSM phase. Additional indications of the SC phase in Cd 3 As 2 were also observed in the point-contact spectroscopy experiments and att...

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Temperature Dependence of the Upper Critical Field in Disordered Hubbard Model with Attraction

Cited by 4 publications

References 34 publications

Ginzburg-Landau expansion and the upper critical field in disordered attractive Hubbard model

Ginzburg-Landau expansion and the upper critical field in disordered attractive Hubbard model

Stabilization of the vortex-liquid state by strong pairing interaction

Observation of subkelvin superconductivity in Cd3As2 thin films

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