Field dependent quasiparticles in a strongly correlated local system

Hewson, A. C.; Bauer, Johannes; Koller, Winfried

doi:10.1103/physrevb.73.045117

Cited by 62 publications

(93 citation statements)

References 36 publications

(99 reference statements)

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“…For stronger fields the shift changes the sign. The result for weak magnetic fields seems to be in disagreement with numerical studies of the model [4] and approximate analytic calculations [5,6]. The initial direction of the shift obtained by us may, however, be changed in the full parquet self-consistency.…”

Section: Spectral Function In the Kondo Regimecontrasting

confidence: 76%

“…We have to resort to approximations. There are a few approximate methods either of numerical [4] or analytic [5,6] character, but their results are inconclusive and incomplete. In this paper we reconsider the effects of the applied magnetic field on the strong-coupling regime of SIAM by using a resummation of the diagrammatic expansion for vertex functions.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic Properties of Metallic Impurities with Strongly Correlated Electrons

Janiš

Ringel

2009

Acta Phys. Pol. A

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We study the single impurity Anderson model in an external magnetic field. There are no exact results for the spectral function in this situation. Using a resummation of the diagrammatic expansion we demonstrate that the strong coupling regime in a weak magnetic field is Kondo-like with a quasiparticle resonant peak split into two. We find two exponentially small Kondo scales (temperatures), one for transverse and one for longitudinal spin fluctuations. We show that the salient features of the spectral function in the Kondo regime can be seen already within an extended random phase approximation. To reveal the dependence of the Kondo scales on the bare electron interaction, however, one has to employ a two-particle self-consistency with renormalized vertices. We use the parquet approach to derive the dependence of the Kondo scales on magnetic field.

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Section: Spectral Function In the Kondo Regimecontrasting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Magnetic Properties of Metallic Impurities with Strongly Correlated Electrons

Janiš

Ringel

2009

Acta Phys. Pol. A

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“…The question naturally arises therefore as to how large does the magnetic field have to be to see this crossover. To answer this question we have calculated the renormalized parameters in a magnetic field 27,34 and used them to deduce the Wilson ratios for the spin and pseudospin, W s and W ps . One way of applying the magnetic field is to adjust the mean level on the dotsε d such thatε d = h − U 12 /2, which, starting at ε d = −U 12 /2, will be such as to maintain the total occupation of the two dots n d,tot = 1.…”

Section: Results In a Field A Crossover As A Function Of Magneticmentioning

confidence: 99%

“…The temperature corrections to order T 2 for the single impurity Anderson model have been calculated exactly in terms of the renormalized parameters using the renormalized perturbation expansion (RPT). [27][28][29] Similar calculations have been carried out for the leading corrections to the linear voltage regime in powers of the bias voltage V , using RPT in the Keldysh formulation. [39][40][41] The approach should be applicable to the double dot model but the calculations are lengthy and will be the subject for future work.…”

Section: Discussionmentioning

confidence: 99%

Analysis of low-energy response and possible emergent SU(4) Kondo state in a double quantum dot

et al. 2013

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We examine the low energy behavior of a double quantum dot in a regime where spin and pseudospin excitations are degenerate. The individual quantum dots are described by Anderson impurity models with an on-site interaction U which are capacitively coupled by an interdot interaction U12 < U . The low energy response functions are expressed in terms of renormalized parameters, which can be deduced from an analysis of the fixed point in a numerical renormalization group calculation. At the point where the spin and pseudospin degrees of freedom become degenerate, the free quasiparticle excitations have a phase shift of π/4 and a 4-fold degeneracy. We find, however, when the quasiparticle interactions are included, that the low energy effective model has SU(4) symmetry only in the special case U12 = U unless both U and U12 are greater than D, the half-bandwidth of the conduction electron bath. We show that the gate voltage dependence of the temperature dependent differential conductance observed in recent experiments can be described by a quasiparticle density of states with temperature dependent renormalized parameters.

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“…In the present calculation, we use field-dependent parameters˜ f (h) and∆ f (h) whose highly non-trivial variation with field is derived from fits to field-dependent quasiparticle DOS of the single-impurity Anderson model. [32][33][34][35] The latter are calculated microscopically by means of the Numerical Renormalization Group (NRG). This procedure properly accounts for the progressive de-renormalization of the quasiparticles with increasing magnetic field and the correlationenhanced Zeeman splitting.…”

Section: Renormalized Bands For Ybrh 2 Simentioning

confidence: 99%

Magnetic Field-Induced Anomalies and Kondo Effect in Lanthanide in Heavy-Electron Systems

Zwicknagl

2011

J. Phys. Soc. Jpn.

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We investigate the influence of magnetic fields on the heavy quasiparticles in the Kondo lattice system YbRh 2 Si 2 and in filled skutterudites containing Pr ions. In the Kramers system YbRh 2 Si 2 the Kondo singlets break up in an applied field which leads to a general reduction of the effective mass. The observed anomalous behavior of the specific heat is quantitatively described by the Renormalized Band method where the field-dependent quasi-particle parameters are deduced from Numerical Renormalization Group calculations for a single Anderson impurity. In filled skutterudites containing the non-Kramers Pr ions, on the other hand, the heavy quasi-particle mass can be explained by aspherical Coulomb scattering of conduction electrons off Crystalline Electric Field excitations. The field-induced splitting of the low-lying triplet should lead to a strongly field-dependent mass enhancement. It is suggested that a field-induced Kondo effect could occur in the dilute system La 1−x Pr x Os 4 Sb 12 in close analogy to the Kondo effect found in integer-spin quantum dots.

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Field dependent quasiparticles in a strongly correlated local system

Cited by 62 publications

References 36 publications

Magnetic Properties of Metallic Impurities with Strongly Correlated Electrons

Magnetic Properties of Metallic Impurities with Strongly Correlated Electrons

Analysis of low-energy response and possible emergent SU(4) Kondo state in a double quantum dot

Magnetic Field-Induced Anomalies and Kondo Effect in Lanthanide in Heavy-Electron Systems

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