CM Seminar at ICTP - Tuesday 10 November at 16:00 Euler Lecture Hall LB

[Condensed Matter Section]

Condensed Matter and Statistical Physics Seminar
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TUESDAY, 10 NOVEMBER, at 16:00 hrs.
Euler Lecture Hall, ICTP Leonardo Building, Terrace Level


Oleg BROVKO
Max-Planck Institute of Microstructure Physics,
Halle (Saale), Germany)


"Controlling Magnetism at the Nanoscale on Metallic and Semi-insulating 
Surfaces"


_Abstract:_

Ultimate control over magnetic properties of nano-scale surface 
structures has been one of the holy grails of the surface-science 
community for quite some time. Among the many ways of achieving this 
control I would like to highlight a few pertaining to metallic and 
semi-insulating surfaces.

For metallic surfaces I shall concentrate of the possibility to control 
surface magnetism with charge doping and external electric field (EEF) 
application, showing that (i) magneto-electric coupling via EEF-based 
charge manipulation is a way to tailor single adatom spins, exchange 
interaction between adsorbates or anisotropies of chains and layered 
systems [1-3]; (ii) the effect of EEF can be enhanced by immersing the 
target system into an electrolyte or ionic liquid [1,4] and (iii) that 
similar physics can be found in charge traps, metallic systems decoupled 
from a bulk electron bath. [1,5]

As powerful tools often turn out to have their drawbacks and side 
effects, also the use of substrate electrons' manipulation for tailoring 
magnetism at the nanoscale often unfavorably affect the dynamics and 
non-ground-state properties of nanostructures due to the electron 
scattering from the substrate's vast electron bath.

I would argue, that a compromise can be found in the use of 
semi-insulating substrates, such as thin layers of CuN, MgO of BN on a 
metallic support. As an example I shall show that (i) electric field can 
also be used on such surfaces to tailor the exchange-coupling of 
magnetic adatoms on MgO/Ag(001) and that (ii) control over the 
nanostructure-substrate coupling in conjunction with hydrogenation opens 
up a possibility to tune the spins of single Co adatoms on corrugated 
hexagonal boron nitride supported on Rh(111) [6]

[1] O. Brovko, P. Ruiz-Di­az, T.R. Dasa, and V.S. Stepanyuk, J. Phys. 
Cond. Matter 26, 093001 (2014) [2] N. Negulyaev, V.S. Stepanyuk, W. 
Hergert, and J. Kirschner, Phys. Rev. Lett. 106, 037202 (2011) [3] T.R. 
Dasa, P.A. Ignatiev, and V.S. Stepanyuk, Phys. Rev. B 85, 205447 (2012) 
[4] L. Juarez-Reyes, G.M. Pastor, and V.S. Stepanyuk, Phys. Rev. B 86, 
235436 (2012) [5] P. Ruiz-Di­az, T.R. Dasa, and V. S. Stepanyuk, Phys. 
Rev. Lett. 110, 267203 (2013) [6] P. Jacobson, T. Herden, M. Muenks, G. 
Laskin, O. Brovko, V. Stepanyuk, M. Ternes, and K. Kern, Nature Commun. 
6, 8536 (2015)