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Reimann J, Sumida K, Kakoki M, Kokh KA, Tereshchenko OE, Kimura A, Güdde J, Höfer U. Ultrafast electron dynamics in a topological surface state observed in two-dimensional momentum space. Sci Rep 2023; 13:5796. [PMID: 37032349 PMCID: PMC10083179 DOI: 10.1038/s41598-023-32811-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 03/31/2023] [Indexed: 04/11/2023] Open
Abstract
We study ultrafast population dynamics in the topological surface state of Sb[Formula: see text]Te[Formula: see text] in two-dimensional momentum space with time- and angle-resolved two-photon photoemission spectroscopy. Linearly polarized mid-infrared pump pulses are used to permit a direct optical excitation across the Dirac point. We show that this resonant excitation is strongly enhanced within the Dirac cone along three of the six [Formula: see text]-[Formula: see text] directions and results in a macroscopic photocurrent when the plane of incidence is aligned along a [Formula: see text]-[Formula: see text] direction. Our experimental approach makes it possible to disentangle the decay of transiently excited population and photocurent by elastic and inelastic electron scattering within the full Dirac cone in unprecedented detail. This is utilized to show that doping of Sb[Formula: see text]Te[Formula: see text] by vanadium atoms strongly enhances inelastic electron scattering to lower energies, but only scarcely affects elastic scattering around the Dirac cone.
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Affiliation(s)
- J Reimann
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032, Marburg, Germany
| | - K Sumida
- Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
- Materials Sciences Research Center, Japan Atomic Energy Agency, Sayo, Hyogo, 679-5148, Japan
| | - M Kakoki
- Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - K A Kokh
- V.S. Sobolev Institute of Geology and Mineralogy SB RAS, 630090, Novosibirsk, Russian Federation
| | - O E Tereshchenko
- Rzhanov Institute of Semiconductor Physics SB RAS, 630090, Novosibirsk, Russian Federation
| | - A Kimura
- Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
- International Institute for Sustainability with Knotted Chiral Meta Matter (SKCM2), 1-3-2 Kagamiyama, Higashi-Hiroshima, 739-8511, Japan
| | - J Güdde
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032, Marburg, Germany.
| | - U Höfer
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032, Marburg, Germany
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2
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Ito S, Schüler M, Meierhofer M, Schlauderer S, Freudenstein J, Reimann J, Afanasiev D, Kokh KA, Tereshchenko OE, Güdde J, Sentef MA, Höfer U, Huber R. Build-up and dephasing of Floquet-Bloch bands on subcycle timescales. Nature 2023; 616:696-701. [PMID: 37046087 DOI: 10.1038/s41586-023-05850-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 02/15/2023] [Indexed: 04/14/2023]
Abstract
Strong light fields have created opportunities to tailor novel functionalities of solids1-5. Floquet-Bloch states can form under periodic driving of electrons and enable exotic quantum phases6-15. On subcycle timescales, lightwaves can simultaneously drive intraband currents16-29 and interband transitions18,19,30,31, which enable high-harmonic generation16,18,19,21,22,25,28-30 and pave the way towards ultrafast electronics. Yet, the interplay of intraband and interband excitations and their relation to Floquet physics have been key open questions as dynamical aspects of Floquet states have remained elusive. Here we provide this link by visualizing the ultrafast build-up of Floquet-Bloch bands with time-resolved and angle-resolved photoemission spectroscopy. We drive surface states on a topological insulator32,33 with mid-infrared fields-strong enough for high-harmonic generation-and directly monitor the transient band structure with subcycle time resolution. Starting with strong intraband currents, we observe how Floquet sidebands emerge within a single optical cycle; intraband acceleration simultaneously proceeds in multiple sidebands until high-energy electrons scatter into bulk states and dissipation destroys the Floquet bands. Quantum non-equilibrium calculations explain the simultaneous occurrence of Floquet states with intraband and interband dynamics. Our joint experiment and theory study provides a direct time-domain view of Floquet physics and explores the fundamental frontiers of ultrafast band-structure engineering.
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Affiliation(s)
- S Ito
- Department of Physics, Philipps-University of Marburg, Marburg, Germany
| | - M Schüler
- Laboratory for Materials Simulations, Paul Scherrer Institute, Villigen PSI, Switzerland
- Department of Physics, University of Fribourg, Fribourg, Switzerland
| | - M Meierhofer
- Department of Physics, University of Regensburg, Regensburg, Germany
| | - S Schlauderer
- Department of Physics, University of Regensburg, Regensburg, Germany
| | - J Freudenstein
- Department of Physics, University of Regensburg, Regensburg, Germany
| | - J Reimann
- Department of Physics, Philipps-University of Marburg, Marburg, Germany
| | - D Afanasiev
- Department of Physics, University of Regensburg, Regensburg, Germany
| | - K A Kokh
- A.V. Rzhanov Institute of Semiconductor Physics and V.S. Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk, Russian Federation
| | - O E Tereshchenko
- A.V. Rzhanov Institute of Semiconductor Physics and V.S. Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk, Russian Federation
| | - J Güdde
- Department of Physics, Philipps-University of Marburg, Marburg, Germany
| | - M A Sentef
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany.
| | - U Höfer
- Department of Physics, Philipps-University of Marburg, Marburg, Germany.
- Department of Physics, University of Regensburg, Regensburg, Germany.
| | - R Huber
- Department of Physics, University of Regensburg, Regensburg, Germany.
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3
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Schmid CP, Weigl L, Grössing P, Junk V, Gorini C, Schlauderer S, Ito S, Meierhofer M, Hofmann N, Afanasiev D, Crewse J, Kokh KA, Tereshchenko OE, Güdde J, Evers F, Wilhelm J, Richter K, Höfer U, Huber R. Tunable non-integer high-harmonic generation in a topological insulator. Nature 2021; 593:385-390. [PMID: 34012087 DOI: 10.1038/s41586-021-03466-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 03/17/2021] [Indexed: 02/04/2023]
Abstract
When intense lightwaves accelerate electrons through a solid, the emerging high-order harmonic (HH) radiation offers key insights into the material1-11. Sub-optical-cycle dynamics-such as dynamical Bloch oscillations2-5, quasiparticle collisions6,12, valley pseudospin switching13 and heating of Dirac gases10-leave fingerprints in the HH spectra of conventional solids. Topologically non-trivial matter14,15 with invariants that are robust against imperfections has been predicted to support unconventional HH generation16-20. Here we experimentally demonstrate HH generation in a three-dimensional topological insulator-bismuth telluride. The frequency of the terahertz driving field sharply discriminates between HH generation from the bulk and from the topological surface, where the unique combination of long scattering times owing to spin-momentum locking17 and the quasi-relativistic dispersion enables unusually efficient HH generation. Intriguingly, all observed orders can be continuously shifted to arbitrary non-integer multiples of the driving frequency by varying the carrier-envelope phase of the driving field-in line with quantum theory. The anomalous Berry curvature warranted by the non-trivial topology enforces meandering ballistic trajectories of the Dirac fermions, causing a hallmark polarization pattern of the HH emission. Our study provides a platform to explore topology and relativistic quantum physics in strong-field control, and could lead to non-dissipative topological electronics at infrared frequencies.
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Affiliation(s)
- C P Schmid
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - L Weigl
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - P Grössing
- Institute of Theoretical Physics, University of Regensburg, Regensburg, Germany
| | - V Junk
- Institute of Theoretical Physics, University of Regensburg, Regensburg, Germany
| | - C Gorini
- Institute of Theoretical Physics, University of Regensburg, Regensburg, Germany.,Université Paris-Saclay, CEA, CNRS, SPEC, Gif-sur-Yvette, France
| | - S Schlauderer
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - S Ito
- Department of Physics, Philipps-University of Marburg, Marburg, Germany
| | - M Meierhofer
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - N Hofmann
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - D Afanasiev
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - J Crewse
- Institute of Theoretical Physics, University of Regensburg, Regensburg, Germany
| | - K A Kokh
- V.S. Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk, Russia.,Novosibirsk State University, Novosibirsk, Russia
| | - O E Tereshchenko
- Novosibirsk State University, Novosibirsk, Russia.,A.V. Rzhanov Institute of Semiconductor Physics SB RAS, Novosibirsk, Russia
| | - J Güdde
- Department of Physics, Philipps-University of Marburg, Marburg, Germany
| | - F Evers
- Institute of Theoretical Physics, University of Regensburg, Regensburg, Germany
| | - J Wilhelm
- Institute of Theoretical Physics, University of Regensburg, Regensburg, Germany.
| | - K Richter
- Institute of Theoretical Physics, University of Regensburg, Regensburg, Germany.
| | - U Höfer
- Department of Physics, Philipps-University of Marburg, Marburg, Germany
| | - R Huber
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany.
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4
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Wallauer R, Raths M, Stallberg K, Münster L, Brandstetter D, Yang X, Güdde J, Puschnig P, Soubatch S, Kumpf C, Bocquet FC, Tautz FS, Höfer U. Tracing orbital images on ultrafast time scales. Science 2021; 371:1056-1059. [PMID: 33602865 DOI: 10.1126/science.abf3286] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 02/01/2021] [Indexed: 11/02/2022]
Abstract
Frontier orbitals determine fundamental molecular properties such as chemical reactivities. Although electron distributions of occupied orbitals can be imaged in momentum space by photoemission tomography, it has so far been impossible to follow the momentum-space dynamics of a molecular orbital in time, for example, through an excitation or a chemical reaction. Here, we combined time-resolved photoemission using high laser harmonics and a momentum microscope to establish a tomographic, femtosecond pump-probe experiment of unoccupied molecular orbitals. We measured the full momentum-space distribution of transiently excited electrons, connecting their excited-state dynamics to real-space excitation pathways. Because in molecules this distribution is closely linked to orbital shapes, our experiment may, in the future, offer the possibility of observing ultrafast electron motion in time and space.
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Affiliation(s)
- R Wallauer
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität Marburg, Renthof 5, 35032 Marburg, Germany
| | - M Raths
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany.,Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany.,Experimentalphysik IV A, RWTH Aachen University, Otto-Blumenthal-Straße, 52074 Aachen, Germany
| | - K Stallberg
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität Marburg, Renthof 5, 35032 Marburg, Germany
| | - L Münster
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität Marburg, Renthof 5, 35032 Marburg, Germany
| | - D Brandstetter
- Institute of Physics, University of Graz, NAWI Graz, 8010 Graz, Austria
| | - X Yang
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany.,Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany.,Experimentalphysik IV A, RWTH Aachen University, Otto-Blumenthal-Straße, 52074 Aachen, Germany
| | - J Güdde
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität Marburg, Renthof 5, 35032 Marburg, Germany
| | - P Puschnig
- Institute of Physics, University of Graz, NAWI Graz, 8010 Graz, Austria
| | - S Soubatch
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany.,Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - C Kumpf
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany.,Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany.,Experimentalphysik IV A, RWTH Aachen University, Otto-Blumenthal-Straße, 52074 Aachen, Germany
| | - F C Bocquet
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany.,Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - F S Tautz
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany. .,Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany.,Experimentalphysik IV A, RWTH Aachen University, Otto-Blumenthal-Straße, 52074 Aachen, Germany
| | - U Höfer
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität Marburg, Renthof 5, 35032 Marburg, Germany.
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5
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Brixius K, Beyer A, Mette G, Güdde J, Dürr M, Stolz W, Volz K, Höfer U. Second-harmonic generation as a probe for structural and electronic properties of buried GaP/Si(0 0 1) interfaces. J Phys Condens Matter 2018; 30:484001. [PMID: 30406767 DOI: 10.1088/1361-648x/aae85b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Optical second-harmonic generation is demonstrated to be a sensitive probe of the buried interface between the lattice-matched semiconductors gallium phosphide and silicon with (0 0 1) orientation. Ex situ rotational anisotropy measurements on GaP/Si heterostructures show a strong isotropic component of the second-harmonic response not present for pure Si(0 0 1) or GaP(0 0 1). The strength of the overlaying anisotropic response directly correlates with the quality of the interface as determined by atomically resolved scanning transmission electron microscopy. Systematic comparison of samples fabricated under different growth conditions in metal-organic vapor phase epitaxy reveals that the anisotropy for different polarization combinations can be used as a selective fingerprint for the occurrence of anti-phase domains and twins. This all-optical technique can be applied as an in situ and non-invasive monitor even during growth.
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Affiliation(s)
- K Brixius
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität Marburg, 35032 Marburg, Germany
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6
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Reimann J, Schlauderer S, Schmid CP, Langer F, Baierl S, Kokh KA, Tereshchenko OE, Kimura A, Lange C, Güdde J, Höfer U, Huber R. Subcycle observation of lightwave-driven Dirac currents in a topological surface band. Nature 2018; 562:396-400. [DOI: 10.1038/s41586-018-0544-x] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/26/2018] [Indexed: 11/09/2022]
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7
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Armbrust N, Güdde J, Höfer U, Kossler S, Feulner P. Spectroscopy and Dynamics of a Two-Dimensional Electron Gas on Ultrathin Helium Films on Cu(111). Phys Rev Lett 2016; 116:256801. [PMID: 27391738 DOI: 10.1103/physrevlett.116.256801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Indexed: 06/06/2023]
Abstract
Electrons in image-potential states on the surface of bulk helium represent a unique model system of a two-dimensional electron gas. Here, we investigate their properties in the extreme case of reduced film thickness: a monolayer of helium physisorbed on a single-crystalline (111)-oriented Cu surface. For this purpose we have utilized a customized setup for time-resolved two-photon photoemission at very low temperatures under ultrahigh vacuum conditions. We demonstrate that the highly polarizable metal substrate increases the binding energy of the first (n=1) image-potential state by more than 2 orders of magnitude as compared to the surface of liquid helium. An electron in this state is still strongly decoupled from the metal surface due to the large negative electron affinity of helium and we find that even 1 monolayer of helium increases its lifetime by 1 order of magnitude compared to the bare Cu(111) surface.
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Affiliation(s)
- N Armbrust
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032 Marburg, Germany
| | - J Güdde
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032 Marburg, Germany
| | - U Höfer
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032 Marburg, Germany
| | - S Kossler
- Physikdepartment E20, Technische Universität München, 85747 Garching, Germany
| | - P Feulner
- Physikdepartment E20, Technische Universität München, 85747 Garching, Germany
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8
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Kuroda K, Reimann J, Güdde J, Höfer U. Generation of Transient Photocurrents in the Topological Surface State of Sb_{2}Te_{3} by Direct Optical Excitation with Midinfrared Pulses. Phys Rev Lett 2016; 116:076801. [PMID: 26943549 DOI: 10.1103/physrevlett.116.076801] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Indexed: 06/05/2023]
Abstract
We combine tunable midinfrared (mid-IR) pump pulses with time- and angle-resolved two-photon photoemission to study ultrafast photoexcitation of the topological surface state (TSS) of Sb_{2}Te_{3}. It is revealed that mid-IR pulses permit a direct excitation from the occupied to the unoccupied part of the TSS across the Dirac point. The novel optical coupling induces asymmetric transient populations of the TSS at ±k_{∥}, which reflects a macroscopic photoexcited electric surface current. By observing the decay of the asymmetric population, we directly investigate the dynamics of the long-lived photocurrent in the time domain. Our discovery promises important advantages of photoexcitation by mid-IR pulses for spintronic applications.
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Affiliation(s)
- K Kuroda
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032 Marburg, Germany
| | - J Reimann
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032 Marburg, Germany
| | - J Güdde
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032 Marburg, Germany
| | - U Höfer
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032 Marburg, Germany
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9
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Armbrust N, Güdde J, Jakob P, Höfer U. Time-resolved two-photon photoemission of unoccupied electronic states of periodically rippled graphene on Ru(0001). Phys Rev Lett 2012; 108:056801. [PMID: 22400950 DOI: 10.1103/physrevlett.108.056801] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Indexed: 05/31/2023]
Abstract
The unoccupied electronic states of epitaxially grown graphene on Ru(0001) have been explored by time- and angle-resolved two-photon photoemission. We identify a Ru derived resonance and a Ru/graphene interface state at 0.91 and 2.58 eV above the Fermi level, as well as three image-potential derived states close to the vacuum level. The most strongly bound, short-lived, and least dispersing image-potential state is suggested to have some quantum-well character with a large amplitude below the graphene hills. The two other image-potential states are attributed to a series of slightly decoupled states. Their lifetimes and dispersions are indicative of electrons moving almost freely above the valley areas of the moiré superstructure of graphene.
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Affiliation(s)
- N Armbrust
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032 Marburg, Germany
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10
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Heyl CM, Güdde J, Höfer U, L'Huillier A. Spectrally resolved maker fringes in high-order harmonic generation. Phys Rev Lett 2011; 107:033903. [PMID: 21838359 DOI: 10.1103/physrevlett.107.033903] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Indexed: 05/31/2023]
Abstract
We investigate macroscopic interference effects in high-order harmonic generation using a Ti:sapphire laser operating at a 100 kHz repetition rate. The structure and behavior of spectral and spatial interference fringes are explained and analytically described by transient phase matching of the long electron trajectory contribution. Time-frequency mapping due to the temporal chirp of the harmonic emission allows us to observe Maker fringes directly in the spectral domain.
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Affiliation(s)
- C M Heyl
- Fachbereich Physik, Philipps-Universität Marburg, D-35032 Marburg, Germany
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11
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Affiliation(s)
- J Güdde
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, D-35032 Marburg, Germany
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12
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Stépán K, Güdde J, Höfer U. Time-resolved measurement of surface diffusion induced by femtosecond laser pulses. Phys Rev Lett 2005; 94:236103. [PMID: 16090486 DOI: 10.1103/physrevlett.94.236103] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2005] [Indexed: 05/03/2023]
Abstract
Diffusion of atomic oxygen on a vicinal Pt111 surface induced by femtosecond laser pulses has been studied using optical second-harmonic generation as a sensitive in situ probe of the step coverage. Time-resolved studies of the hopping rate for step-terrace diffusion with a two-pulse correlation scheme reveal a time constant of 1.5 ps for the energy transfer from the electronic excitation of the substrate to the frustrated translations of the adsorbate.
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Affiliation(s)
- K Stépán
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, D-35032 Marburg, Germany
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13
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Rohleder M, Berthold W, Güdde J, Höfer U. Time-resolved two-photon photoemission of buried interface states in Ar/Cu(100). Phys Rev Lett 2005; 94:017401. [PMID: 15698130 DOI: 10.1103/physrevlett.94.017401] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2004] [Indexed: 05/24/2023]
Abstract
We demonstrate the existence of buried image-potential states at the interface between thick Ar films and a Cu(100) substrate. The electron dynamics of these solid-solid interface states, energetically located above the vacuum level in the band gaps of both materials, could be investigated with time-resolved two-photon photoemission for an Ar layer thickness up to 200 A. Relaxation on time scales between 40 and 200 fs occurs via two distinct channels, resonant tunneling through the insulating layer into the vacuum and electron-hole pair decay in the metal.
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Affiliation(s)
- M Rohleder
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, D-35032 Marburg, Germany
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14
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15
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Freudenberg T, Stert V, Radloff W, Ringling J, Güdde J, Korn G, Hertel I. Ultrafast dynamics of ammonia clusters excited by femtosecond VUV laser pulses. Chem Phys Lett 1997. [DOI: 10.1016/s0009-2614(97)00312-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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16
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Güdde J, Klinkmüller A, West PJ, Matthias E. Second-order magnetic contributions to the hyperfine splitting of the 5snd 1D2 states in 87Sr. Phys Rev A 1993; 47:4725-4734. [PMID: 9909499 DOI: 10.1103/physreva.47.4725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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17
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Sun J, Matthias E, Heber K, West PJ, Güdde J. Impact-broadening cross sections of Rydberg levels of alkaline-earth atoms by collision with rare gases at thermal energy. Phys Rev A 1991; 43:5956-5965. [PMID: 9904924 DOI: 10.1103/physreva.43.5956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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