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I am a graduate student at Rutgers University, Department of Physics and Astronomy. I am involved in theoretical work uder the supervision of Prof. Piers Coleman. In particular i'm interested in the crossover between condensed matter physics and high energy physics, as well as topological properties of realistic materials. (With special interest to a newrly re-discovered Samarium Hexaboride: SmB6)

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End states in a 1-D topological Kondo insulator
(as a guide to explain anomalously fast surface states)


To gain further insight into the properties of interacting topological insulators, we study a 1 dimensional model of topological Kondo insulators which can be regarded as the strongly interacting limit of the Tamm-Shockley model. Treating the model in a large N expansion, we find a number of competing ground-state solutions, including topological insulating and valence bond ground-states. One of the effects to emerge in our treatment is a reconstruction of the Kondo screening process near the boundary of the material (``Kondo band bending'' ). Near the boundary for localization into a valence bond state, we find that the conduction character of the edge state grows substantially, leading to states that extend deeply into bulk. We speculate that such states are the one-dimensional analog of the light f-electron surface states which appear to develop in the putative topological Kondo insulator, SmB6.

Cubic Topological Kondo Insulators
(Mean field, with special application to SmB6.)

this paper was inspired by a 40 years old puzzle of residual resistivity of SmB6 (Samarium Hexaboride). In the paper we refine the criteria that is needed to have conducting surface states, which is now believed to be caused by topology. Such materials are referred as topological insulators.
This paper is in PRL (Physical Review Letters). http://prl.aps.org/abstra...

    "Current theories of Kondo insulators employ the interaction of conduction electrons with localized Kramers doublets originating from a tetragonal crystalline environment, yet all Kondo insulators are cubic. Here we develop a theory of cubic topological Kondo insulators involving the interaction of G8 spin quartets with a conduction sea. The spin quartets greatly increase the potential for strong topological insulators, entirely eliminating the weak topological phases from the diagram. We show that the relevant topological behavior in cubic Kondo insulators can only reside at the lower symmetry X or M points in the Brillouin zone, leading to three Dirac cones with heavy quasiparticles."
  • ***

    My first paper @ Rutgers is an editor's choice in PRB (Physical Review B). http://prb.aps.org...
    It is an attempt to bring together some toy models of AdS/CDFT and Condensed matter community. We ask what are the spin properties in those toy models (Holographic models).

    "In this paper, we discuss two-dimensional holographic metals from a condensed matter physics perspective. We examine the spin structure of the Green's function of the holographic metal, demonstrating that the excitations of the holographic metal are ''helical'', lacking the inversion symmetry of a conventional Fermi surface, with only one spin orientation for each point on the Fermi surface aligned parallel to the momentum. While the presence of a Kramer's degeneracy across the Fermi surface permits the formation of a singlet superconductor, it also implies that ferromagnetic spin fluctuations are absent from the holographic metal, leading to a complete absence of Pauli paramagnetism. In addition, we show how the Green's function of the holographic metal can be regarded as a reflection coefficient in anti-de Sitter space, relating the ingoing and outgoing waves created by a particle moving on the external surface."
  • Impact factors of PRL and PRB are 7.4 and 3.7 respectfully.


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    Hi Vitya! How are you?
    14.05.2011 06:48 - Natal Stone
    Note that we will meet on TASI next month! =)
    26.05.2010 04:57 - Dmitry
    02.05.2010 01:23 - vic