Thermodynamics of the anisotropic two-channel Kondo problem

Zaránd, Gergely; Costi, T. A.; Jerez, Andres; Andrei, Natan

doi:10.1103/physrevb.65.134416

Cited by 23 publications

(29 citation statements)

References 29 publications

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“…Thus, in this particular case, it is expected that the system would have a non-Fermi-liquid ͑nFL͒ ground state below the Kondo temperature T K and above the Kondo temperature, a logarithmic temperature dependence of the electrical resistance, R(T), should be observed. [3][4][5][6] The recent studies have shown that considerable T K can be achieved only outside the tunneling regime, i.e., when the first excited state is above the barrier. 7 In such a case, however, the splitting is significantly larger and hence the nFL region is harder to reach.…”

Section: Introductionmentioning

confidence: 99%

ThAsSe diamagnet: Evidence for a Kondo effect derived from structural two-level systems

et al. 2003

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We report a study of an anomalous scattering mechanism in the structurally disordered diamagnet ThAsSe. Below 20 K, its electrical resistance displays a logarithmic correction over one decade in temperature, which is affected by neither strong magnetic fields (Bр17 T) nor high hydrostatic pressures (pр1.88 GPa). Dynamic disorder in the ThAsSe single crystals is reflected by, e.g., a quasilinear-in-T term of nonelectronic origin in the specific heat at TՇ1.7 K. The ln T dependence of the resistance is interpreted as being due to the interaction of the conduction electrons with movable structural defects.

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Section: Introductionmentioning

confidence: 99%

ThAsSe diamagnet: Evidence for a Kondo effect derived from structural two-level systems

et al. 2003

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“…80. This system has a non-Fermiliquid ground state of the same type as the two-channel Kondo model (2CK) 34,40,50,67,81,82,83,84,85,86,87,88,89,90,91 . For low interimpurity exchange interaction J, the local moment screening occurs in two stages: at the higher Kondo temperature T (1) K the local moments on impurities 1 and 3 are screened, while the local moment on impurity 2 is screened at an exponentially reduced second Kondo temperature T (2) K 80,92 .…”

Section: Introductionmentioning

confidence: 99%

Numerical renormalization group study of two-channel three-impurity triangular clusters

Žitko

Bonča

2008

Phys. Rev. B

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We study triangular clusters of three spin-1/2 Kondo or Anderson impurities that are coupled to two conduction leads. In the case of Kondo impurities, the model takes the form of an antiferromagnetic Heisenberg ring with Kondo-like exchange coupling to continuum electrons. We show that this model exhibits many types of the behavior found in various simpler one and two-impurity models, thereby enabling the study of crossovers between a number of Fermi-liquid (FL) and non-Fermi-liquid (NFL) fixed points. In particular, we explore a direct crossover between the two-impurity Kondo-model NFL fixed point and the two-channel Kondo-model NFL fixed point. We show that the concept of the two-stage Kondo effect applies even in the case when the first-stage Kondo state is of NFL type. In the case of Anderson impurities, we consider the transport properties of three coupled quantum dots. This class of models includes as limiting cases the familiar serial double quantum dot and triple quantum dot nanostructures. By extracting the quasiparticle scattering phase shifts, we compute the low-temperature conductance as a function of the inter-impurity tunneling-coupling. We point out that due to the existence of exponentially low temperature scales, there is a parameter range where the stable "zero-temperature" fixed point is essentially never reached (not even in numerical renormalization group calculations). The "zero-temperature" conductance is then of no interest and it may only be meaningful to compute the conductance at finite temperature. This illustrates the perils of studying the conductance in the ground state and considering thermal fluctuations only as a small correction.

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“…The total number of flavors ͑valleys͒ is . Further motivation to study flavors stems from the fact that in some previous studies of multiply degenerate systems, the number of flavors has not been well defined, for example heavy fermions, [27][28][29] charged domain walls, 30 a superstrong magnetic field, 2 and spin instabilities. 31,32 Cold atom systems in optical lattices [33][34][35] have a well-defined number of flavors but weak interactions between particles.…”

Section: Introductionmentioning

confidence: 99%

Many-flavor electron gas approach to electron-hole drops

Conduit

2008

Phys. Rev. B

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A many-flavor electron gas (MFEG) is analyzed, such as could be found in a multi-valley semiconductor or semimetal. Using the re-derived polarizability for the MFEG an exact expression for the total energy of a uniform MFEG in the many-flavor approximation is found; the interacting energy per particle is shown to be -0.574447E_h a_0^3/4 m*^3/4 n^1/4 with E_h being the Hartree energy, a_0 Bohr radius, and m^* particle effective mass. The short characteristic length-scale of the MFEG motivates a local density approximation, allowing a gradient expansion in the energy density, and the expansion scheme is applied to electron-hole drops, finding a new form for the density profile and its surface scaling properties.Comment: 11 pages, 5 figure

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Thermodynamics of the anisotropic two-channel Kondo problem

Cited by 23 publications

References 29 publications

ThAsSe diamagnet: Evidence for a Kondo effect derived from structural two-level systems

ThAsSe diamagnet: Evidence for a Kondo effect derived from structural two-level systems

Numerical renormalization group study of two-channel three-impurity triangular clusters

Many-flavor electron gas approach to electron-hole drops

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