Forum DQMP

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Day / Time
Date(s) - 23/02/2016
13 h 00 min - 14 h 00 min

Category


Tuesday, February 23rd 2016 – 13h00
Auditoire Stückelberg
Ecole de physique

Coffee and tea will be available from 12h50 at the entrance of the Auditoire

 

Structure of self-assembled manganese atom chains on Si(001) surface
Renan Villarreal (group of Prof. Renner)

Electrons confined to one dimension are expected to develop remarkable properties, both static and
dynamic. Modeling and understanding the electronic properties of atomic chains requires a detailed
knowledge of their structure. Recently, manganese (Mn) has been found to self-assemble into atomic
chains running perpendicular to the surface dimer reconstruction on Si(001). They differ from other
atomic chains by a striking asymmetric appearance in filled state scanning tunneling microscopy (STM)
images. In this talk, I will describe our combined STM, atomic force microscopy and density functional
theory study of Mn chains on Si(001). Our results reveal that a model based on a simple necklace-like
chain of single Mn atoms reproduces all their prominent features, including their asymmetry not
captured by the previously proposed models. The upshot is a remarkably simpler structure for
modeling the electronic and magnetic properties of Mn atom chains on Si(001).

 

AFM-written conducting nanostructures at LaAlO3/SrTiO3 interfaces
Margherita Boselli (group of Prof. Triscone)

The realization of conducting nanostructures at the interface between LaAlO3 and SrTiO3 is an
important step towards the realization of devices and the investigation of exotic physical regimes.
These systems combine the interesting properties emerging in low dimensions with the complex
behavior of oxides.
I will present a detailed study of the conducting nanowires realized using the AFM-writing technique[1].
By comparing experiments with numerical simulations, we show that these wires reproduce the ideal
case of nano conducting channels defined in an insulating background very well and that the tip bias is
a powerful knob to modulate the size of these structures. I will also discuss the role of the air humidity
that is found to be a crucial parameter to set the size of the tip-sample effective interaction area.

[1] Cen, C. Thiel, S. et al. Nat Mater 7, 298–302 (2008).

Forum Committee : L. Foini, C. Lichtensteiger, N. Ubrig (12.02.2016)

Réalisation : Sur Mesure concept