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Li F, Miao W, Yu C, He Z, Wang Q, Zhong J, Wu F, Wang Z, Zhou K, Ren Y, Zhang W, Li J, Shi S, Liu Q, Feng Z. Low-Temperature Thermal Transport Characteristics in Epitaxial Bilayer Graphene Microbridges. ACS OMEGA 2024; 9:23053-23059. [PMID: 38826519 PMCID: PMC11137710 DOI: 10.1021/acsomega.4c02727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 04/25/2024] [Accepted: 05/07/2024] [Indexed: 06/04/2024]
Abstract
In this paper, we present a study of the thermal transport of epitaxial bilayer graphene microbridges. The thermal conductance of three graphene microbridges with different lengths was measured at different temperatures using Johnson noise thermometry. We find that with the decrease of the temperature, the thermal transport in the graphene microbridges switches from electron-phonon coupling to electron diffusion, and the switching temperature is dependent on the length of the microbridge, which is in good agreement with the simulation based on a distributed hot-spot model. Moreover, the electron-phonon thermal conductance has a temperature power law of T3 as predicted for pristine graphene and the electron-phonon coupling coefficient σep is found to be approximately 0.18 W/(m2 K4), corresponding to a deformation potential D of 55 eV. In addition, the electron diffusion in the graphene microbridges adheres to the Wiedemann-Franz law, requiring no corrections to the Lorentz number.
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Affiliation(s)
- Feiming Li
- Purple
Mountain Observatory, Chinese Academy of Sciences, Nanjing 210033, China
- University
of Science and Technology of China, Hefei 230026, China
| | - Wei Miao
- Purple
Mountain Observatory, Chinese Academy of Sciences, Nanjing 210033, China
| | - Cui Yu
- National
Key Laboratory of Solid-State Microwave Devices and Circuits, Shijiazhuang 050051, China
| | - Zezhao He
- National
Key Laboratory of Solid-State Microwave Devices and Circuits, Shijiazhuang 050051, China
| | - Qingcheng Wang
- Purple
Mountain Observatory, Chinese Academy of Sciences, Nanjing 210033, China
- University
of Science and Technology of China, Hefei 230026, China
| | - Jiaqiang Zhong
- Purple
Mountain Observatory, Chinese Academy of Sciences, Nanjing 210033, China
| | - Feng Wu
- Purple
Mountain Observatory, Chinese Academy of Sciences, Nanjing 210033, China
| | - Zheng Wang
- Purple
Mountain Observatory, Chinese Academy of Sciences, Nanjing 210033, China
| | - Kangmin Zhou
- Purple
Mountain Observatory, Chinese Academy of Sciences, Nanjing 210033, China
| | - Yuan Ren
- Purple
Mountain Observatory, Chinese Academy of Sciences, Nanjing 210033, China
| | - Wen Zhang
- Purple
Mountain Observatory, Chinese Academy of Sciences, Nanjing 210033, China
| | - Jing Li
- Purple
Mountain Observatory, Chinese Academy of Sciences, Nanjing 210033, China
| | - Shengcai Shi
- Purple
Mountain Observatory, Chinese Academy of Sciences, Nanjing 210033, China
| | - Qingbin Liu
- National
Key Laboratory of Solid-State Microwave Devices and Circuits, Shijiazhuang 050051, China
| | - Zhihong Feng
- National
Key Laboratory of Solid-State Microwave Devices and Circuits, Shijiazhuang 050051, China
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2
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Heber M, Wind N, Kutnyakhov D, Pressacco F, Arion T, Roth F, Eberhardt W, Rossnagel K. Multispectral time-resolved energy-momentum microscopy using high-harmonic extreme ultraviolet radiation. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:083905. [PMID: 36050085 DOI: 10.1063/5.0091003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 07/18/2022] [Indexed: 06/15/2023]
Abstract
A 790-nm-driven high-harmonic generation source with a repetition rate of 6 kHz is combined with a toroidal-grating monochromator and a high-detection-efficiency photoelectron time-of-flight momentum microscope to enable time- and momentum-resolved photoemission spectroscopy over a spectral range of 23.6-45.5 eV with sub-100 fs time resolution. Three-dimensional (3D) Fermi surface mapping is demonstrated on graphene-covered Ir(111) with energy and momentum resolutions of ≲100 meV and ≲0.1 Å-1, respectively. The tabletop experiment sets the stage for measuring the kz-dependent ultrafast dynamics of 3D electronic structure, including band structure, Fermi surface, and carrier dynamics in 3D materials as well as 3D orbital dynamics in molecular layers.
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Affiliation(s)
- Michael Heber
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Nils Wind
- Institut für Experimental Physik, Universität Hamburg, 22761 Hamburg, Germany
| | | | | | - Tiberiu Arion
- Centre for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Friedrich Roth
- Institute of Experimental Physics, TU Bergakademie Freiberg, 09599 Freiberg, Germany
| | - Wolfgang Eberhardt
- Centre for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Kai Rossnagel
- Ruprecht Haensel Laboratory, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
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3
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Sforzini J, Nemec L, Denig T, Stadtmüller B, Lee TL, Kumpf C, Soubatch S, Starke U, Rinke P, Blum V, Bocquet FC, Tautz FS. Approaching truly freestanding graphene: the structure of hydrogen-intercalated graphene on 6H-SiC(0001). PHYSICAL REVIEW LETTERS 2015; 114:106804. [PMID: 25815955 DOI: 10.1103/physrevlett.114.106804] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Indexed: 06/04/2023]
Abstract
We measure the adsorption height of hydrogen-intercalated quasifreestanding monolayer graphene on the (0001) face of 6H silicon carbide by the normal incidence x-ray standing wave technique. A density functional calculation for the full (6√3×6√3)-R30° unit cell, based on a van der Waals corrected exchange correlation functional, finds a purely physisorptive adsorption height in excellent agreement with experiments, a very low buckling of the graphene layer, a very homogeneous electron density at the interface, and the lowest known adsorption energy per atom for graphene on any substrate. A structural comparison to other graphenes suggests that hydrogen-intercalated graphene on 6H-SiC(0001) approaches ideal graphene.
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Affiliation(s)
- J Sforzini
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - L Nemec
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany
| | - T Denig
- Max Planck Institute for Solid State Research, Heisenbergstraße, 70569 Stuttgart, Germany
| | - B Stadtmüller
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - T-L Lee
- Diamond Light Source Ltd, Didcot, OX110DE Oxfordshire, United Kingdom
| | - 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
| | - 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
| | - U Starke
- Max Planck Institute for Solid State Research, Heisenbergstraße, 70569 Stuttgart, Germany
| | - P Rinke
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany
- COMP/Department of Applied Physics, Aalto University, P.O. Box 11100, Aalto FI-00076, Finland
| | - V Blum
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany
- Department of Mechanical Engineering and Material Science, Duke University, Durham, North Carolina 27708, USA
| | - 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
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4
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Ulstrup S, Johannsen JC, Grioni M, Hofmann P. Extracting the temperature of hot carriers in time- and angle-resolved photoemission. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:013907. [PMID: 24517782 DOI: 10.1063/1.4863322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The interaction of light with a material's electronic system creates an out-of-equilibrium (non-thermal) distribution of optically excited electrons. Non-equilibrium dynamics relaxes this distribution on an ultrafast timescale to a hot Fermi-Dirac distribution with a well-defined temperature. The advent of time- and angle-resolved photoemission spectroscopy (TR-ARPES) experiments has made it possible to track the decay of the temperature of the excited hot electrons in selected states in the Brillouin zone, and to reveal their cooling in unprecedented detail in a variety of emerging materials. It is, however, not a straightforward task to determine the temperature with high accuracy. This is mainly attributable to an a priori unknown position of the Fermi level and the fact that the shape of the Fermi edge can be severely perturbed when the state in question is crossing the Fermi energy. Here, we introduce a method that circumvents these difficulties and accurately extracts both the temperature and the position of the Fermi level for a hot carrier distribution by tracking the occupation statistics of the carriers measured in a TR-ARPES experiment.
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Affiliation(s)
- Søren Ulstrup
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark
| | - Jens Christian Johannsen
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Marco Grioni
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Philip Hofmann
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark
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5
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Mazzola F, Wells JW, Yakimova R, Ulstrup S, Miwa JA, Balog R, Bianchi M, Leandersson M, Adell J, Hofmann P, Balasubramanian T. Kinks in the σ band of graphene induced by electron-phonon coupling. PHYSICAL REVIEW LETTERS 2013; 111:216806. [PMID: 24313515 DOI: 10.1103/physrevlett.111.216806] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Indexed: 05/09/2023]
Abstract
Angle-resolved photoemission spectroscopy reveals pronounced kinks in the dispersion of the σ band of graphene. Such kinks are usually caused by the combination of a strong electron-boson interaction and the cutoff in the Fermi-Dirac distribution. They are therefore not expected for the σ band of graphene that has a binding energy of more than ≈3.5 eV. We argue that the observed kinks are indeed caused by the electron-phonon interaction, but the role of the Fermi-Dirac distribution cutoff is assumed by a cutoff in the density of σ states. The existence of the effect suggests a very weak coupling of holes in the σ band not only to the π electrons of graphene but also to the substrate electronic states. This is confirmed by the presence of such kinks for graphene on several different substrates that all show a strong coupling constant of λ≈1.
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Affiliation(s)
- Federico Mazzola
- Department of Physics, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway
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Craciun MF, Khrapach I, Barnes MD, Russo S. Properties and applications of chemically functionalized graphene. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:423201. [PMID: 24045655 DOI: 10.1088/0953-8984/25/42/423201] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The vast and yet largely unexplored family of graphene materials has great potential for future electronic devices with novel functionalities. The ability to engineer the electrical and optical properties in graphene by chemically functionalizing it with a molecule or adatom is widening considerably the potential applications targeted by graphene. Indeed, functionalized graphene has been found to be the best known transparent conductor or a wide gap semiconductor. At the same time, understanding the mechanisms driving the functionalization of graphene with hydrogen is proving to be of fundamental interest for energy storage devices. Here we discuss recent advances on the properties and applications of chemically functionalized graphene.
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Affiliation(s)
- M F Craciun
- Centre for Graphene Science, College of Engineering, Mathematics, and Physical Sciences, University of Exeter, Exeter EX4 4QL, UK
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7
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Johannsen JC, Ulstrup S, Cilento F, Crepaldi A, Zacchigna M, Cacho C, Turcu ICE, Springate E, Fromm F, Raidel C, Seyller T, Parmigiani F, Grioni M, Hofmann P. Direct view of hot carrier dynamics in graphene. PHYSICAL REVIEW LETTERS 2013; 111:027403. [PMID: 23889442 DOI: 10.1103/physrevlett.111.027403] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Indexed: 05/25/2023]
Abstract
The ultrafast dynamics of excited carriers in graphene is closely linked to the Dirac spectrum and plays a central role for many electronic and optoelectronic applications. Harvesting energy from excited electron-hole pairs, for instance, is only possible if these pairs can be separated before they lose energy to vibrations, merely heating the lattice. Until now, the hot carrier dynamics in graphene could only be accessed indirectly. Here, we present a dynamical view on the Dirac cone by time- and angle-resolved photoemission spectroscopy. This allows us to show the quasi-instant thermalization of the electron gas to a temperature of ≈2000 K, to determine the time-resolved carrier density, and to disentangle the subsequent decay into excitations of optical phonons and acoustic phonons (directly and via supercollisions).
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Affiliation(s)
- Jens Christian Johannsen
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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