Project

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Local electronic and magnetic properties of metal atomic chains

Applicant Renner Christoph
Number 119978
Funding scheme Project funding (Div. I-III)
Research institution Département de Physique de la Matière Condensée Université de Genève
Institution of higher education University of Geneva - GE
Main discipline Condensed Matter Physics
Start/End 01.09.2008 - 31.08.2011
Approved amount 565'786.00
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Keywords (8)

Spintronics; Single atom wire; Tunneling spectroscopy; Scanning tunneling microscopy; Spin polarized scanning tunneling microscopy; Low dimensional magnetism; Luttinger liquid; 1D systems

Lay Summary (English)

Lead
Lay summary
Introduction and MotivationsThis project aims at exploring novel avenues to uncover the intrinsic properties of one dimensional structures. 1D systems host a range of fascinating and exotic physical phenomena such as quantum phase transitions, spin-charge separation and Luttinger liquid behaviour, magnetic and charge ordering. Atomic chains of metal atoms are perhaps the ultimate embodiment of 1D physics, susceptible to feature novel properties not present in higher dimensional assemblies of the same atoms, such as superconductivity. Furthermore, reduction in the coordination of metal atoms on a surface leads to enhanced magnetic properties such as the magnetic anisotropy energy. It may even induce magnetism in nonmagnetic elements. Understanding these phenomena is of fundamental interest, and their control holds huge potential for a number of applications in spintronics, magnetic storage, and quantum computing, to name only a few.Research PlanAccessing the intrinsic properties of single atom chains in an experiment is very challenging. They cannot usually be made free standing, and there will always be some degree of coupling between the electronic states of the chain atoms and those of a substrate. The magnetic properties of surface metal atoms depend strongly upon the degree of interaction with the substrate which is especially large in metal-on-metal systems. We plan to grow metal atomic chains on a weakly-interacting semiconducting substrate to produce systems closer to that of an ideal isolated atomic chain.We shall study two examples of metal atom chains on silicon: Firstly, the well-characterized Au/Si(553) system, which exhibits an unusual feature of a doublet of half-filled states, and a quarter-filled state whose origins remain unclear. We aim to determine the real-space location of these states and their magnetic character, using Spin-Resolved STM, thus connecting previous STM experiments of low-lying states on Si atoms within the reconstruction, and the half-filled states detected by Angle-Resolved Photoemission (ARPES). Secondly, we shall fabricate atomic chains using a nanoline templating method, whereby metal atoms are deposited onto a surface containing self-assembled Bi nanolines on a passivated background. These systems will provide a route for the study of many aspects of 1D physics, leading eventually to their integration into real devices through the silicon substrate (e.g. solid-state magnetic storage, interconnects and quantum information processing).
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Electronic structure of Bi lines on clean and H-passivated Si(100)
Javorsky J, Owen JHG, Setvin M, Miki K, Electronic structure of Bi lines on clean and H-passivated Si(100), in JOURNAL OF PHYSICS-CONDENSED MATTER, 22(17).
Endotaxial Si nanolines in Si(001):H
Bianco F, Owen JHG, Koster SA, Mazur D, Renner C, Bowler DR, Endotaxial Si nanolines in Si(001):H, in PHYSICAL REVIEW B, 84(3).
Manganese silicide nanowires on Si(001)
Liu HJ, Owen JHG, Miki K, Renner C, Manganese silicide nanowires on Si(001), in JOURNAL OF PHYSICS-CONDENSED MATTER, 23(17).
One-dimensional Si-in-Si(001) template for single-atom wire growth
Owen JHG, Bianco F, Koster SA, Mazur D, Bowler DR, Renner C, One-dimensional Si-in-Si(001) template for single-atom wire growth, in APPLIED PHYSICS LETTERS, 97(9).

Collaboration

Group / person Country
Types of collaboration
London Centre for Nanotechnology Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
ECOSS 2011 Talk given at a conference One-dimensional Mn atom chains and Bi nanolines on a Si(001) surface 28.08.2011 Wroclav, Poland, Poland Köster Sigrun Antje;
Swiss Physical Society Meeting Talk given at a conference Endotaxial Si nanolines in hydrogen covered Si(001) 15.06.2011 Lausanne, Switzerland, Switzerland Bianco François;
APS March Meeting 2011 Talk given at a conference Endotaxial Si nanolines in Si(001):H 21.03.2011 Dallas, USA, United States of America Owen James Hugh Gervase;
Annual meeting of German Physical Society Talk given at a conference One-dimensional Mn atom chains templated on a Si(001) surface 13.03.2011 Dresden, Germany, Germany Köster Sigrun Antje;
Swiss-Swedish meeting on "Quantum Materials and Devices" Talk given at a conference Superconductivity and charge stripe instability in intercalated graphite 07.01.2011 Les Diablerets, Switzerland, Sweden Renner Christoph;
Swiss Physical Society Meeting Talk given at a conference Novel Si-in-Si one dimensional template for atomic chains 21.06.2010 Basel, Switzerland, Switzerland Renner Christoph; Bianco François;
Annual meeting of German Physical Society Talk given at a conference One-dimensional Mn atom chains templated on a Si(001) surface 21.03.2010 Regensburg, Germany, Germany Köster Sigrun Antje;
MANA International Symposium Talk given at a conference Structure and Electronic Properties of Self-Assembled Si-in-Si(001) Nanowire 03.03.2010 Tsukuba, Japan, Japan Owen James Hugh Gervase;
Nanostructures at Surfaces Talk given at a conference Bi-nanowire templates on Si(001) for single atom wire growth 21.09.2009 Monte Verita, Switzerland, Switzerland Renner Christoph;


Self-organised

Title Date Place
Swiss workshop on materials with novel electronic properties 2011 29.06.2011 Les Diablerets, Switzerland, Switzerland
Swiss workshop on materials with novel electronic properties 2009 26.08.2009 Les Diablerets, Switzerland, Switzerland

Communication with the public

Communication Title Media Place Year
Talks/events/exhibitions Atomes à portée de main, synthèse et maîtrise de la matière à l'échelle atomique Western Switzerland 2011
Talks/events/exhibitions La matière à l'ère des nanotechnologies Western Switzerland 2011
Talks/events/exhibitions Les nanotechnologies: promesse ou menace Western Switzerland 2011
Talks/events/exhibitions Les nanotechnologies sont parmis nous Western Switzerland 2009

Associated projects

Number Title Start Funding scheme
133777 Scanning probe microscopy and spectroscopy of nanoscale materials and devices 01.01.2011 R'EQUIP
135198 Electronic, magnetic and transport properties of one-dimensional systems 01.09.2011 Project funding (Div. I-III)

Abstract

The present proposal aims at exploring novel avenues to uncover the intrinsic properties of metal atomic chains, capitalizing on our unique combination of long standing experiences in atom wire growth on silicon and in scanning probe imaging and spectroscopy. One dimensional structures, of which atomic chains of metal atoms are perhaps the ultimate embodiment, host a range of fascinating and exotic physical phenom-ena. Strong electron-electron and electron-phonon interactions induced by the reduced dimensionality may yield Luttinger liquid behaviour, spin-charge separation, magnetic and charge ordering, quantum phase tran-sitions and possibly novel properties not present in higher dimensional assemblies of the same atoms, such as superconductivity. Furthermore, reduction in the coordination of metal atoms on a surface leads to en-hanced magnetic properties such as the magnetic anisotropy energy. It may even induce magnetism in nonmagnetic elements. Understanding these phenomena is of fundamental interest, and their control holds huge potential for a number of applications in spintronics, magnetic storage, and quantum computing, to name only a few. We have an ambitious goal to fabricate atomic chains on a weakly-interacting substrate, so as to retain their intrinsic properties.Accessing the intrinsic properties of single atom chains in an experiment is very challenging. They cannot usually be made free standing, and there will always be some degree of coupling between the electronic states of the chain atoms and those of the substrate. The magnetic properties of surface metal atoms de-pend strongly upon the degree of interaction which is especially large in metal-on-metal systems. This cou-pling to the substrate can be reduced by passivation of the surface (e.g. CuN on Cu) or by using a semicon-ducting or insulating substrate (e.g. the Au/Si(55n) systems). Decoupling from the substrate may help avoid unwanted Peierls distortions. On the other hand, the weak coupling behaviour may be a route to explore and tune the interaction of a Luttinger liquid with an electron bath. To achieve our goal, atomic chains will be grown on a nanoline template substrate. We expect very little coupling of the atom wires to this substrate, and hence for them to retain their intrinsic character. We shall gain insight into their intrinsic properties using scanning probe imaging and spectroscopy (and perhaps non local techniques such as photoemission and magnetometry). In particular, we shall characterise the atom wires using spin-polarised scanning tunneling microscopy (SP-STM) to explore the local spin character of the chains and thereby close the gap between large scale spectroscopic measurements and conventional STM observations. We plan to use a novel STM based spin detection technique we are currently developing following a proposal by Bruno. Although it is in principle restricted to measuring the magnetization parallel to the substrate, it has a number of advantages over more conventional SP-STM techniques involving ferro- and antiferromagnetic tips, in particular the absence of any magnetic stray field and the possibility to probe simultaneously minority and majority spin carriers. Note that for the weakly-coupled systems that we aim to fabricate, the easy magnetization direction may lie in the plane of the substrate, which can be more challeng-ing to measure than out of plane magnetization using the above more conventional magnetic tips. We shall study two examples of metal atom chains on silicon: Firstly, the well-characterized Au/Si(553) sys-tem, which exhibits an unusual feature of a doublet of half-filled states, and a ¼-filled state whose origins remain unclear. We aim to determine the real-space location of these states and their magnetic character, thus connecting previous STM experiments of low-lying states on Si atoms within the reconstruction, and the half-filled states detected by Angle-Resolved Photoemission (ARPES). This will also serve as a test system for the Mott-STM. Secondly, we shall fabricate atomic chains using a nanoline templating method, whereby metal atoms are deposited onto a surface containing self-assembled Bi nanolines in a passivated back-ground, where a recent in-depth DFT study predicts that atomic chains and nanowires 1-3 atoms wide can be formed under suitable growth conditions. Fabricating such chains will be a significant challenge, but it is worthwhile as we expect the low-lying electronic states of the atomic chains to be localized on the metal at-oms, and therefore largely decoupled from the substrate. Such systems will be much closer to an ideal atomic chain than the Au/Si(553) system, thus providing a route for the study of many aspects of 1D metal properties, and eventually integrating them into real devices through the silicon substrate (e.g. solid-state magnetic storage, interconnects and quantum information processing).
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