ELFT HÍRADÓ

[tcsaba AT eik.bme.hu]

                                   MEGHÍVÓ

              a BME Fizikai Intézete Elméleti Fizika Tanszékének

                               szemináriumára:


                                 J. Cayssol
                     (LOMA and Université de Bordeaux)


                "Persistent and dissipative currents around
                   two-dimensional topological insulators"


Quantum spin Hall insulators are two-dimensional band insulators  
characterized by protected counter-propagating one-dimensional (1D)  
metallic edge states. This 1D edge metal is unique because the spin of  
its carriers is tied to their direction of motion, and backscattering  
between right and left movers is forbidden by time-reversal symmetry.  
I will describe the response of these helical edge states under flux  
biasing. For a static flux, the edge Dirac fermions carry a persistent  
current which is robust to non magnetic disorder [1]. For  
time-dependent flux biasing, the response of the 1D helical liquid is  
characterized by a complex susceptibility. The relaxation time of the  
edge carriers can be determined from a measurement of the dissipative  
part of this susceptibility [2]. The effects of various perturbations,  
including Zeeman coupling and disorder, will also be discussed. In  
conclusion, I will also discuss briefly the connection with the  
Floquet topological insulators with photo induced edge states [3].

[1] D. Sticlet and J. Cayssol, Phys. Rev. B 90, 201303 (2014).
[2] D. Sticlet, B. Dóra, and J. Cayssol, Phys. Rev. B 88, 205401 (2013).
[3] J. Cayssol, B. Dóra, F. Simon, and R. Moessner, Phys. Status  
Solidi RRL, 7, 101 (2013).


Helye: BME Fizikai Intézet, Elméleti Fizika Tanszék
Budafoki út 8. F-épület, III lépcsöház
Szemináriumi szoba

Ideje: 2015. május 28. csütörtök, 13:15.


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