Abstract
In this communication, we report surface state, with Rashba impurities, of a generic topological Kondo insulator (TKI) system by performing a mean-field theoretic (MFT) calculation within the framework of slave-boson protocol. The surface metallicity together with bulk insulation is found to require very strong f-electron localization. The possibility of intra-band as well as inter-band unconventional plasmons exists for the surface state spectrum. The paramountcy of the bulk metallicity, and, in the presence of the Rashba impurities, the TKI surface comprising of ‘helical liquids’ are the important outcomes of the present communication. The access to the gapless Dirac spectrum leads to spin-plasmons with the usual wave vector dependence q1/2. The Rashba coupling does not impair the Kondo screening and does not affect the quantum critical point (QCP) for the bulk.
Highlights
The Periodic Anderson model (PAM) [1,2,3,4,5,6] basically involves highly correlated electrons in one f -orbital, which are screened by weakly correlated electrons in a second d orbital
We have started with PAM—a model for a generic topological Kondo insulator (TKI)
For almost filled f -bands this corresponds to projecting out the states with two or more f -particles per site
Summary
The Periodic Anderson model (PAM) [1,2,3,4,5,6] basically involves highly correlated electrons (localized magnetic moments) in one f -orbital, which are screened by weakly correlated electrons in a second d orbital. Unlike the well-known topological insulators, such as Bi2 Se3 family of materials, in TKIs the strong correlation effects among the 4f -electrons are very important It brings about the strong modification of the 4f -band width. MFT involves condensing the boson field and neglecting all of its dynamics This effectively leads to a non-interacting model of an insulator, where the gap is proportional to the condensate and hybridization parameter, and makes it amenable to a topological analysis. The paper is organized as follows: In Section 2, we consider a model for a (topological) Kondo insulator on a simple cubic lattice with one spin-degenerate orbital per lattice site each for d and f -electrons with Hubbard type interaction term (U) between the latter. The paper ends with a short discussion and concluding remarks at the end
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