Anisotropic coupling of individual vibrational modes to a Cu(110) substrate.
Phys Chem Chem Phys
; 25(35): 23894-23900, 2023 Sep 13.
Article
em En
| MEDLINE
| ID: mdl-37642506
ABSTRACT
We present a study on the excitation of individual vibrational modes with ballistic charge carriers propagating along the Cu(110) surface. By means of the molecular nanoprobe technique, where the reversible switching of a molecule-in this case tautomerization of porphycene-is utilized to detect excitation events, we reveal anisotropic coupling of two distinct vibrational modes to the substrate. The N-H bending mode, excited below |E| ≈ 376 meV, exhibits maxima perpendicular to the rows of the Cu(110) substrate and minima along the rows. In contrast, the N-H stretching mode, excited above |E| ≈ 376 meV, displays maxima along the rows and is constant otherwise. This inversion of the anisotropy reflects the orthogonality between the N-H bending and stretching mode. Additionally, we observe an energy-dependent asymmetry in the propagation direction of charge carriers injected into the Cu(110) surface state. Hereby, the anisotropic band structure results in a correlation between the group velocity and the tunneling probability into electronic states of the substrate.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Phys Chem Chem Phys
Assunto da revista:
BIOFISICA
/
QUIMICA
Ano de publicação:
2023
Tipo de documento:
Article
País de afiliação:
Alemanha