Considerable evidence exists for the failure of the traditional theory of quantum critical points, pointing to the need to incorporate novel excitations. The destruction of Kondo entanglement and the concomitant critical Kondo effect may underlie these emergent excitations in heavy fermion metals (a prototype system for quantum criticality), but the effect remains poorly understood. Here, we sh...

In this Thesis we develop a novel direction in the theory of nano-objects, i.e., structures of nanometer size in a tunnel contact with macroscopic electron reservoirs (metallic leads). This theory arose and was developed rapidly during the two recent decades as a response to challenging achievements of modern nanotechnology and experimental techniques. Evolution of this technology enabled the f...

– We study the Kondo effect in a quantum dot embedded in a mesoscopic ring taking into account intradot spin-flip scattering R. Based on the finite-U slave-boson mean-field approach, we find that the Kondo peak in the density of states is split into two peaks by this coherent spin-flip transition, which is responsible for some interesting features of the Kondo-assisted persistent current circul...

Non-equilibrium tunneling current in a Kondo system subject to both constant and alternating electric fields is studied. First, a time-dependent Schrieffer-Wolff transformation is performed, mapping the time-dependent Anderson Hamiltonian onto a Kondo one. Then, a perturbation expansion in powers of the coupling strength is carried out up to third order, yielding a simple analytical expression ...

Submitted for the MAR11 Meeting of The American Physical Society Enhancement of Kondo effect through Rashba spin-orbit interactions1 NANCY SANDLER, MEHDI ZAREA, SERGIO ULLOA, Ohio University — The role of Rashba spin-orbit (RSO) interactions on the Kondo regime has been a topic of debate since resistivity measurements on Pt doped Cu:Mn compounds were interpreted as evidence for suppression of t...

In the Kondo effect, a localized magnetic moment is screened by forming a correlated electron system with the surrounding conduction electrons of a non-magnetic host 1. Spin S = 1/2 Kondo systems have been investigated extensively in theory and experiments, but magnetic atoms often have a larger spin 2. Larger spins are subject to the influence of magneto-crystalline anisotropy, which describes...

We repeat our previous calculation about the effect of the spin-orbit-induced magnetic anisotropy on the Kondo temperature in the case of S = 5/2 impurity spin which is quite different from the integer spin case as the ground state is degenerated. In this case the Kondo contribution remains finite when the sample size goes to zero and the thickness dependence in the Kondo resistivity is much mo...

We study the two-dimensional periodic Anderson model at half-filling using quantum Monte Carlo (QMC) techniques. The ground state undergoes a magnetic order-disorder transition as a function of the effective exchange coupling between the conduction and localized bands. Low-lying spin and charge excitations are determined using the maximum entropy method to analytically continue the QMC data. At...

– We study the competition between the Kondo effect and frustrating exchange interactions in a Kondo-lattice model within a large-N dynamical mean-field theory. We find a T = 0 phase transition between a heavy Fermi-liquid and a spin-liquid for a critical value of the exchange Jc = T 0 K , the single-impurity Kondo temperature. Close to the critical point, the Fermi liquid coherence scale T ⋆ i...

A theory is proposed to describe the competition among antiferromagnetism (AF), spin glass (SG) and Kondo effect. The model describes two Kondo sublattices with an intrasite Kondo interaction strength JK and a random Gaussian interlattice interaction in the presence of a transverse field Γ. The Γ field is introduced as a quantum mechanism to produce spin flipping and the random coupling has ave...