Simple extension of the plane-wave final state in photoemission: Bringing understanding to the photon-energy dependence of two-dimensional materials
Angle-resolved photoemission spectroscopy (ARPES) is a method that measures orbital and band structure contrast through the momentum distribution of photoelectrons. Its simplest interpretation is obtained in the plane-wave approximation, according to which photoelectrons propagate freely to the dete...
| Main Authors: | , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Physical Society
2023-08-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/PhysRevResearch.5.033075 |
| _version_ | 1797210424384421888 |
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| author | Christian S. Kern Anja Haags Larissa Egger Xiaosheng Yang Hans Kirschner Susanne Wolff Thomas Seyller Alexander Gottwald Mathias Richter Umberto De Giovannini Angel Rubio Michael G. Ramsey François C. Bocquet Serguei Soubatch F. Stefan Tautz Peter Puschnig Simon Moser |
| author_facet | Christian S. Kern Anja Haags Larissa Egger Xiaosheng Yang Hans Kirschner Susanne Wolff Thomas Seyller Alexander Gottwald Mathias Richter Umberto De Giovannini Angel Rubio Michael G. Ramsey François C. Bocquet Serguei Soubatch F. Stefan Tautz Peter Puschnig Simon Moser |
| author_sort | Christian S. Kern |
| collection | DOAJ |
| description | Angle-resolved photoemission spectroscopy (ARPES) is a method that measures orbital and band structure contrast through the momentum distribution of photoelectrons. Its simplest interpretation is obtained in the plane-wave approximation, according to which photoelectrons propagate freely to the detector. The photoelectron momentum distribution is then essentially given by the Fourier transform of the real-space orbital. While the plane-wave approximation is remarkably successful in describing the momentum distributions of aromatic compounds, it generally fails to capture kinetic-energy-dependent final-state interference and dichroism effects. Focusing our present study on quasi-freestanding monolayer graphene as the archetypical two-dimensional (2D) material, we observe an exemplary E_{kin}-dependent modulation of, and a redistribution of spectral weight within, its characteristic horseshoe signature around the K[over ¯] and K[over ¯]^{′} points: both effects indeed cannot be rationalized by the plane-wave final state. Our data are, however, in remarkable agreement with ab initio time-dependent density functional simulations of a freestanding graphene layer and can be explained by a simple extension of the plane-wave final state, permitting the two dipole-allowed partial waves emitted from the C 2p_{z} orbitals to scatter in the potential of their immediate surroundings. Exploiting the absolute photon flux calibration of the Metrology Light Source, this scattered-wave approximation allows us to extract E_{kin}-dependent amplitudes and phases of both partial waves directly from photoemission data. The scattered-wave approximation thus represents a powerful yet intuitive refinement of the plane-wave final state in photoemission of 2D materials and beyond. |
| first_indexed | 2024-04-24T10:10:22Z |
| format | Article |
| id | doaj.art-1f96c5fc73904716893738cc3e7965bf |
| institution | Directory Open Access Journal |
| issn | 2643-1564 |
| language | English |
| last_indexed | 2024-04-24T10:10:22Z |
| publishDate | 2023-08-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Research |
| spelling | doaj.art-1f96c5fc73904716893738cc3e7965bf2024-04-12T17:32:57ZengAmerican Physical SocietyPhysical Review Research2643-15642023-08-015303307510.1103/PhysRevResearch.5.033075Simple extension of the plane-wave final state in photoemission: Bringing understanding to the photon-energy dependence of two-dimensional materialsChristian S. KernAnja HaagsLarissa EggerXiaosheng YangHans KirschnerSusanne WolffThomas SeyllerAlexander GottwaldMathias RichterUmberto De GiovanniniAngel RubioMichael G. RamseyFrançois C. BocquetSerguei SoubatchF. Stefan TautzPeter PuschnigSimon MoserAngle-resolved photoemission spectroscopy (ARPES) is a method that measures orbital and band structure contrast through the momentum distribution of photoelectrons. Its simplest interpretation is obtained in the plane-wave approximation, according to which photoelectrons propagate freely to the detector. The photoelectron momentum distribution is then essentially given by the Fourier transform of the real-space orbital. While the plane-wave approximation is remarkably successful in describing the momentum distributions of aromatic compounds, it generally fails to capture kinetic-energy-dependent final-state interference and dichroism effects. Focusing our present study on quasi-freestanding monolayer graphene as the archetypical two-dimensional (2D) material, we observe an exemplary E_{kin}-dependent modulation of, and a redistribution of spectral weight within, its characteristic horseshoe signature around the K[over ¯] and K[over ¯]^{′} points: both effects indeed cannot be rationalized by the plane-wave final state. Our data are, however, in remarkable agreement with ab initio time-dependent density functional simulations of a freestanding graphene layer and can be explained by a simple extension of the plane-wave final state, permitting the two dipole-allowed partial waves emitted from the C 2p_{z} orbitals to scatter in the potential of their immediate surroundings. Exploiting the absolute photon flux calibration of the Metrology Light Source, this scattered-wave approximation allows us to extract E_{kin}-dependent amplitudes and phases of both partial waves directly from photoemission data. The scattered-wave approximation thus represents a powerful yet intuitive refinement of the plane-wave final state in photoemission of 2D materials and beyond.http://doi.org/10.1103/PhysRevResearch.5.033075 |
| spellingShingle | Christian S. Kern Anja Haags Larissa Egger Xiaosheng Yang Hans Kirschner Susanne Wolff Thomas Seyller Alexander Gottwald Mathias Richter Umberto De Giovannini Angel Rubio Michael G. Ramsey François C. Bocquet Serguei Soubatch F. Stefan Tautz Peter Puschnig Simon Moser Simple extension of the plane-wave final state in photoemission: Bringing understanding to the photon-energy dependence of two-dimensional materials Physical Review Research |
| title | Simple extension of the plane-wave final state in photoemission: Bringing understanding to the photon-energy dependence of two-dimensional materials |
| title_full | Simple extension of the plane-wave final state in photoemission: Bringing understanding to the photon-energy dependence of two-dimensional materials |
| title_fullStr | Simple extension of the plane-wave final state in photoemission: Bringing understanding to the photon-energy dependence of two-dimensional materials |
| title_full_unstemmed | Simple extension of the plane-wave final state in photoemission: Bringing understanding to the photon-energy dependence of two-dimensional materials |
| title_short | Simple extension of the plane-wave final state in photoemission: Bringing understanding to the photon-energy dependence of two-dimensional materials |
| title_sort | simple extension of the plane wave final state in photoemission bringing understanding to the photon energy dependence of two dimensional materials |
| url | http://doi.org/10.1103/PhysRevResearch.5.033075 |
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