1
|
Benedek G, Bernasconi M, Campi D, Silkin IV, Chernov IP, Silkin VM, Chulkov EV, Echenique PM, Toennies JP, Anemone G, Al Taleb A, Miranda R, Farías D. Evidence for a spin acoustic surface plasmon from inelastic atom scattering. Sci Rep 2021; 11:1506. [PMID: 33452337 PMCID: PMC7810840 DOI: 10.1038/s41598-021-81018-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 12/29/2020] [Indexed: 11/09/2022] Open
Abstract
Closed-shell atoms scattered from a metal surface exchange energy and momentum with surface phonons mostly via the interposed surface valence electrons, i.e., via the creation of virtual electron-hole pairs. The latter can then decay into surface phonons via electron-phonon interaction, as well as into acoustic surface plasmons (ASPs). While the first channel is the basis of the current inelastic atom scattering (IAS) surface-phonon spectroscopy, no attempt to observe ASPs with IAS has been made so far. In this study we provide evidence of ASP in Ni(111) with both Ne atom scattering and He atom scattering. While the former measurements confirm and extend so far unexplained data, the latter illustrate the coupling of ASP with phonons inside the surface-projected phonon continuum, leading to a substantial reduction of the ASP velocity and possibly to avoided crossing with the optical surface phonon branches. The analysis is substantiated by a self-consistent calculation of the surface response function to atom collisions and of the first-principle surface-phonon dynamics of Ni(111). It is shown that in Ni(111) ASP originate from the majority-spin Shockley surface state and are therefore collective oscillation of surface electrons with the same spin, i.e. it represents a new kind of collective quasiparticle: a Spin Acoustic Surface Plasmon (SASP).
Collapse
Affiliation(s)
- G Benedek
- Dipartimento di Scienza dei Materiali, Universitá di Milano-Bicocca, Via R. Cozzi 55, 20125, Milan, Italy.,Donostia International Physics Center (DIPC), 20018, San Sebastián/Donostia, Basque Country, Spain
| | - M Bernasconi
- Dipartimento di Scienza dei Materiali, Universitá di Milano-Bicocca, Via R. Cozzi 55, 20125, Milan, Italy
| | - D Campi
- Dipartimento di Scienza dei Materiali, Universitá di Milano-Bicocca, Via R. Cozzi 55, 20125, Milan, Italy.,École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - I V Silkin
- Tomsk State University, 634050, Tomsk, Russia
| | - I P Chernov
- Engineering School of Nuclear Technology, Tomsk Polytechnic University, 634050, Tomsk, Russia
| | - V M Silkin
- Donostia International Physics Center (DIPC), 20018, San Sebastián/Donostia, Basque Country, Spain.,Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología, Facultad de Ciencias Químicas, Universidad del País Vasco UPV/EHU, 20080, San Sebastián/Donostia, Basque Country, Spain.,IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Basque Country, Spain
| | - E V Chulkov
- Donostia International Physics Center (DIPC), 20018, San Sebastián/Donostia, Basque Country, Spain.,Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología, Facultad de Ciencias Químicas, Universidad del País Vasco UPV/EHU, 20080, San Sebastián/Donostia, Basque Country, Spain.,Centro de Fisica de Materiales, Centro Mixto CSIC-UPV/EHU, 20018, San Sebastian/Donostia, Basque Country, Spain.,St. Petersburg State University, 198504, St. Petersburg, Russia
| | - P M Echenique
- Donostia International Physics Center (DIPC), 20018, San Sebastián/Donostia, Basque Country, Spain.,Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología, Facultad de Ciencias Químicas, Universidad del País Vasco UPV/EHU, 20080, San Sebastián/Donostia, Basque Country, Spain.,Centro de Fisica de Materiales, Centro Mixto CSIC-UPV/EHU, 20018, San Sebastian/Donostia, Basque Country, Spain
| | - J P Toennies
- Max-Planck-Institut für Dynamik und Selbstorganisation, Bunsenstraße 10, 37073, Göttingen, Germany
| | - G Anemone
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - A Al Taleb
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - R Miranda
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049, Madrid, Spain.,Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), 28049, Madrid, Spain.,Instituto "Nicolás Cabrera", Universidad Autónoma de Madrid, 28049, Madrid, Spain.,Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - D Farías
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049, Madrid, Spain. .,Instituto "Nicolás Cabrera", Universidad Autónoma de Madrid, 28049, Madrid, Spain. .,Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049, Madrid, Spain.
| |
Collapse
|
2
|
Abstract
The reactivity of a Pd monolayer epitaxially grown on Ru(0001) toward O2 has been investigated by molecular beam techniques. O2 initial sticking coefficients were determined using the King and Wells method in the incident energy range of 40-450 meV and for sample temperatures of 100 K and 300 K, and compared to the corresponding values measured on the clean Ru(0001) and Pd(111) surfaces. In contrast to the high reactivity shown by Ru(0001) at 100 K, the Pd/Ru(0001) system exhibits a monotonic decrease in the sticking probability of O2 as a function of normal incident energy. At room temperature, the system was found to be inert. Thermal desorption measurements show that O2 is adsorbed molecularly at 100 K. A completely different behaviour has been measured for the Pd0.95Ru0.05/Ru(0001) surface alloy. On this surface, the O2 sticking probability increases with incident energy and resembles the one observed on the clean Ru(0001) surface, even at 300 K. Thermal desorption measurements point to dissociative adsorption of O2 in this system. Both the charge transfer from the Pd to the Ru substrate and the compressive strain on the Pd monolayer contribute to decrease in the reactivity of the Pd/Ru(0001) system well below those of both Ru(0001) and Pd(111).
Collapse
Affiliation(s)
- D Farías
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - M Minniti
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - R Miranda
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| |
Collapse
|
3
|
Maccariello D, Al Taleb A, Calleja F, Vázquez de Parga AL, Perna P, Camarero J, Gnecco E, Farías D, Miranda R. Observation of Localized Vibrational Modes of Graphene Nanodomes by Inelastic Atom Scattering. Nano Lett 2016; 16:2-7. [PMID: 26630565 DOI: 10.1021/acs.nanolett.5b02887] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Inelastic helium atom scattering (HAS) is suitable to determine low-energy (few meV) vibrations spatially localized on structures in the nanometer range. This is illustrated for the nanodomes that appear often on graphene (Gr) epitaxially grown on single crystal metal surfaces. The nature of the inelastic losses observed in Gr/Ru(0001) and Gr/Cu/Ru(0001) has been clarified by intercalation of Cu below the Gr monolayer, which decouples the Gr layer from the Ru substrate and changes substantially the out-of-plane, flexural phonon dispersion of epitaxial Gr, while maintaining the nanodomes and their localized vibrations. He diffraction proves that the Cu-intercalated Gr layer is well ordered structurally, while scanning tunneling microscopy reveals the persistence of the (slightly modified) periodic array of Gr nanodomes. A simple model explains the order of magnitude of the energy losses associated with the Gr nanodomes and their size dependence. The dispersionless, low-energy phonon branches may radically alter the transport of heat in intercalated Gr.
Collapse
Affiliation(s)
- D Maccariello
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), 28049 Madrid, Spain
| | | | - F Calleja
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), 28049 Madrid, Spain
| | - A L Vázquez de Parga
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), 28049 Madrid, Spain
| | - P Perna
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), 28049 Madrid, Spain
| | - J Camarero
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), 28049 Madrid, Spain
| | - E Gnecco
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), 28049 Madrid, Spain
| | | | - R Miranda
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), 28049 Madrid, Spain
| |
Collapse
|
5
|
Minniti M, Díaz C, Fernández Cuñado JL, Politano A, Maccariello D, Martín F, Farías D, Miranda R. Helium, neon and argon diffraction from Ru(0001). J Phys Condens Matter 2012; 24:354002. [PMID: 22898880 DOI: 10.1088/0953-8984/24/35/354002] [Citation(s) in RCA: 8] [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] [Indexed: 06/01/2023]
Abstract
We present an experimental and theoretical study of He, Ne and Ar diffraction from the Ru(0001) surface. Close-coupling calculations were performed to estimate the corrugation function and the potential well depth in the atom-surface interaction in all three cases. DFT (density functional theory) calculations, including van der Waals dispersion forces, were used to validate the close-coupling results and to further analyze the experimental results. Our DFT calculations indicate that, in the incident energy range 20-150 meV, anticorrugating effects are present in the case of He and Ar diffraction, whereas normal corrugation is observed with Ne beams.
Collapse
Affiliation(s)
- M Minniti
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid, Spain
| | | | | | | | | | | | | | | |
Collapse
|
9
|
Díaz C, Busnengo HF, Rivière P, Farías D, Nieto P, Somers MF, Kroes GJ, Salin A, Martín F. A classical dynamics method for H2 diffraction from metal surfaces. J Chem Phys 2005; 122:154706. [PMID: 15945655 DOI: 10.1063/1.1878613] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
We present a discretization method that allows one to interpret measurements on diffraction of diatomic molecules from solid surfaces using six-dimensional (6D) classical trajectory calculations. It has been applied to the D2NiAl(110) and H2Pd(111) systems (which are models for activated and nonactivated dissociative chemisorption, respectively) using realistic potential energy surfaces obtained from first principles. Comparisons with experimental results and 6D quantum dynamical calculations show that, in general, the method is able to predict the relative intensity of the most important diffraction peaks. We therefore conclude that classical mechanics can be an efficient guide for experimentalists in the search for the most significant diffraction channels.
Collapse
Affiliation(s)
- C Díaz
- Departamento de Química, Facultad de Ciencias C-9, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | | | | | | | | | | | | | | | | |
Collapse
|