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Spin physics and electron dynamics at surfaces, interfaces and in ordered molecular layers

English title Spin physics and electron dynamics at surfaces, interfaces and in ordered molecular layers
Applicant Osterwalder Jürg
Number 124691
Funding scheme Project funding (Div. I-III)
Research institution Physik-Institut Universität Zürich
Institution of higher education University of Zurich - ZH
Main discipline Condensed Matter Physics
Start/End 01.04.2009 - 31.03.2011
Approved amount 605'213.00
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Keywords (18)

molecular films; photoemission; synchrotron radiation; scanning probes; femtosecond lasers; molecular spintronics; self-assembly; graphene; boron nitride; magnetic molecules; Rashba effect; quantum well states; ultrafast demagnetization; negative electron affinity; photoemission synchrotron radiation; femtosecond laser; self assembly; ultrafast magnetization

Lay Summary (English)

Lead
Lay summary
This proposal consists of three subprojects that are related to each other and offer broad synergies. In project A we continue to investigate modern template surfaces for molecular self-assembly based on hexagonal boron nitride or graphene layers on transition metals. In order to connect molecule arrays formed on these templates to the macroscopic world we will implement two new experimental techniques: the detection of light-emission from individual molecules in scanning tunneling microscope junctions and the in-situ resistance measurement in thin metal films covered by templated molecular layers. The choice of molecules is driven by the specific questions that are addressed, like e.g. how negatively charged molecules are immobilized on sp2 templates, or how single electron spins can be controlled in an sp2 templated molecular nanostructure. A second activity will explore new approaches for the formation of double layers, with one particular focus being the growth of graphene / boron nitride heterostructures. With the implementation of the mu-metal shielding around the detector, our spin-resolved photoemission end station at the SLS has become a successful and unique facility for studying spin systems on surfaces. In project B the focus lies primarily on momentum dependent spin-structures in low dimensional systems, induced by the Rashba effect and related spin-orbit-interaction induced effects. Specifically, the tuning of the spin splitting in quantum well states in few monolayer thick Pb films on Si(111) by interface engineering will be studied, as well as the influence of alloying Bi, Pb and Sb on Ag(111) surfaces on the resulting spin structures of the surface states.In project C, transient processes occurring on a femtosecond timescale on surfaces are studied by means of time-resolved photoelectron spectroscopy. This research focuses on the phenomenon of ultrafast magnetization dynamics in thin ferromagnetic films, exploiting the constant energy surface mapping capabilities of an electron display analyzer for pump-probe experiments; this project includes the final setup of the display analyzer and the development of a high-harmonic generation setup for UV-pulses. Moreover, the properties and dynamics of negative electron affinity surfaces, in particular diamondoid layers on pre-patterned surfaces like the boron nitride nanomesh will be investigated.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Associated projects

Number Title Start Funding scheme
129861 Resonant X-ray Photoelectron Diffraction (RXPD) of magnetic molecules 01.09.2010 Project funding (Div. I-III)
122703 Boron nitride nanomesh as a template for guided self-assembly of molecular arrays 01.10.2008 Sinergia
116096 Static and dynamic phenomena on solid surfaces, interfaces and in nanostructures 01.04.2007 Project funding (Div. I-III)
135321 Spin physics and electron dynamics at surfaces, interfaces and in ordered molecular layers 01.04.2011 Project funding (Div. I-III)
150017 Periodic strain fields in graphene and hexagonal boron-nitride on transition metal substrates 01.02.2014 Project funding (Div. I-III)
132509 Periodic strain fields in graphene and hexagonal boron-nitride on transition metal substrates 01.02.2011 Project funding (Div. I-III)
128715 Spin structures in novel and low dimensional materials, studied by spin and angle resolved photoemission 01.05.2010 R'EQUIP

Abstract

This proposal consists of three subprojects that are related to each other and offer broad synergies. In project A we continue to investigate modern template surfaces for molecular self-assembly based on hexagonal boron nitride or graphene layers on transition metals. In order to connect molecule arrays formed on these templates to the macroscopic world we will implement two new experimental techniques: the detection of light-emission from individual molecules in scanning tunneling microscope junctions and the in-situ resistance measurement in thin metal films covered by templated molecular layers. The choice of molecules is driven by the specific questions that are addressed, like e.g. how negatively charged molecules are immobilized on sp2 templates, or how single electron spins can be controlled in an sp2 templated molecular nanostructure. A second activity will explore new approaches for the formation of double layers, with one particular focus on the growth of graphene / boron nitride heterostructures. With the implementation of the mu-metal shielding around the detector, our spin-resolved photoemission end station at the SLS has become a successful and unique facility for studying spin systems on surfaces. In project B the focus lies primarily on momentum dependent spin-structures in low dimensional systems, induced by the Rashba effect and related spin-orbit-interaction induced effects. Specifically, the tuning of the spin splitting in quantum well states in few monolayer thick Pb films on Si(111) by interface engineering will be studied, as well as the influence of alloying Bi, Pb and Sb on Ag(111) surfaces on the resulting spin structures of the surface states.In project C, transient processes occurring on a femtosecond timescale on surfaces are studied by means of time-resolved photoelectron spectroscopy. This research focuses on the phenomenon of ultrafast magnetization dynamics in thin ferromagnetic films, exploiting the constant energy surface mapping capabilities of an electron display analyzer for pump-probe experiments; this project includes the final setup of the display analyzer and the development of a high-harmonic generation setup for UV-pulses. Moreover, the properties and dynamics of negative electron affinity surfaces, in particular diamondoid layers on pre-patterned surfaces like the boron nitride nanomesh will be investigated.
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