[seminar] 03.07.2017. Igor Žutić:

[Damir Pajic]

Drage kolegice i kolege,
Drago mi je da mogu najaviti sljedeć‡i Seminar Fizičkog odsjeka:

Dear colleagues,
I would like to invite you to the following Seminar of the Department of 
Physics:

ponedjeljak/Monday  03.07.2017. u 10.00 h
room F201 (floor II)

Magnetic Proximity Effects:
 From Graphene and Topological Insulators
to Majorana Fermions

Prof. dr. Igor Žutić
University at Buffalo, State University of New York

Proximity effects can transform a given material through its adjacent 
regions to become su perconducting, magnetic, or topologically 
nontrivial. The intuition about the proximity effects is well derived 
from the superconducting case, known for 85 years [1]. Superconducting 
properties can leak out from a superconductor into a neighboring normal 
region which by itself would not be superconducting [2]. Remarkably, 
superconducting proximity effects can attain orders of magnitude longer 
lengths than for magnetic proximity effects that are usually neglected 
in bulk materials. However, in monolayer van der Waals materials, such 
as graphene or transition metal dichalcogenides, the situation can be 
drastically different, even short-range magnetic proximity effects 
exceed their thickness [3,4]. We show that gate-tunable magnetic 
proximity effects in graphene heterostructures lead to the magnitude and 
the sign change of the spin polarization of the density of states in 
graphene [3]. While proximity effects are usually considered equilibrium 
phenomena (zero bias), in a simple topological  insulator/ferromagnet 
junction we predict they are also responsible for unexplored 
nonequilibrium properties, including a novel Hall effect [4].
An interplay between superconducting and magnetic proximity effects can 
lead to the formation of emergent Majorana bound states which are 
neither Fermions, nor Bosons. Instead, exchanging these states yields a 
non-commutative phase, a sign of non-Abelian statistics and non-local
degrees of freedom considered to implement fault-tolerant quantum 
computing [5]. We will discuss novel two-dimensional (2D) platform to 
realize braiding of Majorana bound states [6] and how it can overcome 
the limitations of typical proposals relying on 1D structures [7,8].

[1] R. Holm and W. Meissner, Z. Phys. 74, 75 (1932)
[2] O. T. Valls, M. Bryan, and I. Žutić, Phys. Rev. B 82, 134534 (2010)
[3] P. Lazić, K. D. Belashchenko, and I. Žutić, Phys. Rev. B 93, 
241401(R) (2016)
[4] B. Scharf, G. Xu, A. Matos-Abiague, and I. Žutić, arXiv:1704.07984, 
preprint
[5] C. Nayak et al., Rev. Mod. Phys. 80, 1083 (2008)
[6] G. L. Fatin, A. Matos-Abiague, B. Scharf, and I. Žutić, Phys. Rev. 
Lett. 117, 077002
(2016); A. Matos-Abiague, J. Shabani, A. D. Kent, G. L. Fatin, B. 
Scharf, and I. Žutić, Sol. Stat. Commun. 262, 1 (2017)
[7] V. Mourik, et al., Science 336, 1003 (2012)
[8] S. Nadj-Perge, et al., Science 346, 602 (2014)


Cjeloviti oglas je u prilogu./Formatted announcement is attached.

Lijep pozdrav / Best regards
Damir Pajić





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