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Femtosecond Time- and Angle-Resolved Photoelectron Spectroscopy on Novel Quantum Materials

English title Femtosecond Time- and Angle-Resolved Photoelectron Spectroscopy on Novel Quantum Materials
Applicant Leuenberger Dominik
Number 151328
Funding scheme Advanced Postdoc.Mobility
Research institution Institute for Material and Energy Science Stanford University
Institution of higher education Institution abroad - IACH
Main discipline Condensed Matter Physics
Start/End 01.04.2014 - 31.03.2015
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Keywords (8)

Angle-Resolved Photoelectron Spectroscopy (ARPES); Solid State Physics; Time-and Angle-Resolved Photoelectron Spectroscopy; Topological Insulators; Collective Excitations in Correlated Materials; Charge Density Wave Systems; Femtosecond Laser Pulses; Novel Quantum Materials

Lay Summary (German)

Lead
Charge Density Wave (CDW) Systeme sind eine Klasse von Materialien mit speziell gekoppelten strukturellen und elektronischen Eigenschaften. Unterhalb einer kritischen Temperatur führt die starke Korrelation zwischen den Elektronen und den quantisierten Schwingungen des Kristallgitters zu einem elektronischen Phasenübergang. Charakteristisch dafür sind eine elektronische Bandlücke und eine vom Gitter abweichende periodische Modulation der Ladungsdichte, eine sogenannte Charge Density Wave.
Lay summary

Inhalt und Ziel des Forschungsprojekts

Übergeordnetes Ziel dieses Projekts ist es, schnelle elektronische Anregungen am Phasenübergang von CDW Oberflächen auf der sehr kurzen Femto- bis Pikosekunden Zeitskala direkt zu messen. Durchgeführt wird dies mit Hilfe von zeit- und winkelaufgelöster Elektronenspektroskopie. Der spezielle Ansatz besteht darin mit variablen Photonenenergien anzuregen. Ziel ist es, diese Energien auf die elektronische Bandlücke der zu untersuchenden CDW Materialien abzustimmen. Einerseits erlaubt dies präzisere Anregungen und somit klarere Signale, andererseits können dadurch die verantwortlichen elektronischen Übergänge für den transienten CDW Phasenübergang eruiert werden.

 

Wissenschaftlicher und gesellschaftlicher Kontext des Forschungsprojekts

  1. Diese Arbeit ist fürs fundamentale physikalische Verständnis von elektronischen Streuprozessen untereinander und mit anderen Quasiteilchen in korrelierten Materialien von Bedeutung. Die Erkenntnisse im Bereich von CDW Materialien unterstützen zum Beispiel das Verständnis der Hochtemperatur Supraleitung in Cupraten.

  2. Im Weiteren sollen die Experimente auch helfen einen neuen methodischen Ansatz innerhalb der zeit- und winkelaufgelösten Photoelektronen Spektroskopie zu etablieren. Die Anregung mit variabel abgestimmten Photonenenergien soll zukünftig auch bei anderen neuen Quantenmaterialen angewandt werden.

 

 

Direct link to Lay Summary Last update: 07.01.2014

Responsible applicant and co-applicants

Publications

Publication
Classification of Collective Modes in a Charge Density Wave by Momentum-Dependent Modulation of the Electronic Band Structure
D. Leuenberger, J. A. Sobota, S.-L. Yang, A. F. Kemper, P. Giraldo-Gallo, R. G. Moore, I. R. Fisher, P. S. Kirchmann, T. P. Devereaux, Z.-X. Shen (2015), Classification of Collective Modes in a Charge Density Wave by Momentum-Dependent Modulation of the Electronic Band Structure, in Physical Review B, 91, 201106(R).
Direct characterization of photo-induced lattice dynamics in BaFe2As2
S. Gerber, K. W. Kim, Y. Zhang, D. Zhu, N. Plonka, M. Yi, G. L. Dakowski, D. Leuenberger, P. S. Kirchmann, R. G. Moore, M. Chollet, J. M. Glowina, Y. Feng, J.-S. Lee, A. Metha, A. F. Kemper, T. Wolf, Y.-D. Chuang, Z. Hussain, C.-C. Kao, B. Moritz, Z.-X. Shen, T. P. Devereaux, W. S. Lee (2015), Direct characterization of photo-induced lattice dynamics in BaFe2As2, in Nature Communications, 10.1038/nc.
Thickness-Dependent Coherent Phonon Frequency in Ultrathin FeSe/ SrTiO3 Films
Shuolong Yang, Jonathan A. Sobota, Dominik Leuenberger, Alexander F. Kemper, James J. Lee, Felix T. Schmitt, Wei Li, Rob G. Moore, Patrick S. Kirchmann, Zhi-Xun Shen (2015), Thickness-Dependent Coherent Phonon Frequency in Ultrathin FeSe/ SrTiO3 Films, in Nano Letters, DOI: 10.10.
Distinguishing Bulk and Surface Electron-Phonon Coupling in the Topological Insulator Bi2Se3 Using Time-Resolved Photoemission Spectroscopy
Sobota J. A., Yang S. -L., Leuenberger D., Kemper A. F., Analytis J. G., Fisher I. R., Kirchmann P. S., Devereaux T. P., Shen Z. -X. (2014), Distinguishing Bulk and Surface Electron-Phonon Coupling in the Topological Insulator Bi2Se3 Using Time-Resolved Photoemission Spectroscopy, in PHYSICAL REVIEW LETTERS, 113(15), 157401-1-157401-5.
Ultrafast electron dynamics in the topological insulator Bi2Se3 studied by time-resolved photoemission spectroscopy
Sobota J. A., Yang S. -L., Leuenberger D., Kemper A. F., Analytis J. G., Fisher I. R., Kirchmann P. S., Devereaux T. P., Shen Z. -X. (2014), Ultrafast electron dynamics in the topological insulator Bi2Se3 studied by time-resolved photoemission spectroscopy, in JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA, 195, 249-257.
Inequivalence of Single-Particle and Population Lifetimes in a Cuprate Superconductor
S. Yang, J. A. Sobota, D. Leuenberger, Y. He, M. Hashimoto, D. H. Lu, H. Eisaki, P. S. Kirchmann, Z.-X. Shen, Inequivalence of Single-Particle and Population Lifetimes in a Cuprate Superconductor, in Physical Review Letters.

Collaboration

Group / person Country
Types of collaboration
SIMES Institut, Stanfor University United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel
PULSE Institut, Stanford Linear Accelerator Laboratory (SLAC) United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel
Lawrence Berkeley National Laboratory United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel
Departement of Complex Matter vom Jozef Stefan Institute, Ljubljana Slovenia (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
University of California, Irvine United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Swiss Light Source, Paul Scherrer Institut Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel
University of Bristol 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
MRS Spring Meeting 2015 Talk given at a conference Classification of Collective Modes in a Charge Density Wave by Momentum Dependent Modulation of the Electronic Bandstructure 06.04.2015 San Francisco, Kalifornien, United States of America Leuenberger Dominik;
APS March Meeting 2015 Talk given at a conference Near Gap Excitation of Collective Modes in a Charge Density Wave 02.03.2015 San Antonio, Texas, United States of America Leuenberger Dominik;
LCLS/SSRL Users's Meeting 2014 Poster Near Gap Excitation of the Amplidude Mode in CeTe3 07.10.2014 Stanford Linear Accelerator Laboratory, Menlo Park, Kalifornien, United States of America Leuenberger Dominik;


Knowledge transfer events

Active participation

Title Type of contribution Date Place Persons involved
Stanford Splash (organized by Stanford Optical Society) 08.11.2014 Stanford, Kalifornien, United States of America Leuenberger Dominik;
Bay Area Science Festival 23.10.2014 San Francisco, Kalifornien, United States of America Leuenberger Dominik;


Associated projects

Number Title Start Funding scheme
147271 Femtosecond Time- and Angle-Resolved Photoelectron Spectroscopy on Novel Quantum Materials 01.04.2013 Fellowships for prospective researchers

Abstract

The search for materials with novel electronic properties is an important topic within condensed matter physics. The novel quantum material class of topological insulators reveal the existence of metallic surface states at the boundary of the insulating crystal. Due to strong spin-orbit interaction, the spin and momentum of the electrons in these states are intimately coupled, which provides channels to drive spin-polarized currents at the surface. Understanding how excited electrons in these spin-textured surface states scatter with electrons in surface and bulk states as well as other quasi-particles excitations is crucial for the design of future spintronic devices. Femtosecond time- and angle-resolved photoelectron spectroscopy (trARPES) is currently developing into a profound tool for material science and offers the opportunity to investigate these electron-electron scattering processes in topological insulators directly in the time-domain.In another class of materials, the Charge Density Wave (CDW) systems, strong electron-phonon coupling connects periodic lattice distortions with an electronic metal-to-insulator phase transition. Despite the fact, that trARPES allows for ultrafast excitation and subsequent monitoring of collective modes, still little is known about the coupling strength of the distinct modes in these prototypical CDW materials.The project proposed here will investigate the non-equilibrium electronic structure and corresponding scattering processes on thin films of the topological insulator Bi2Se3 and on RTe3 CDW systems by means of trARPES experiments. This will bring new insight into the scattering rates of non-equilibrium electronic populations in topological insulators as well as into the coupling strength between distinct collective excitations in CDW systems, respectively. The experiments will be performed in the group of Prof. Z.-X. Shen at the Geballe Laboratory for Advanced Materials at Stanford University, offering a combination between photoemission experiment, material growth and theory.
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