Giant phonon-induced conductance in scanning tunnelling spectroscopy of gate-tunable graphene
By Yuanbo Zhang, V. Brar, Feng Wang, Ç. Girit, Yossi Yayon, M. Panlasigui, A. Zettl, M. Crommie. 2008
446 citations recorded by the source corpus.
Scanning tunnelling spectra of a graphene field-effect transistor reveal an unexpected tenfold increase in conductance as a result of phonon-mediated inelastic tunnelling. The honeycomb lattice of graphene is a unique two-dimensional system where the quantum mechanics of electrons is equivalent to that of relativistic Dirac fermions1,2. Novel nanometre-scale behaviour in this material, including electronic scattering3,4, spin-based phenomena5 and collective excitations6, is predicted to be sensitive to charge-carrier density. To probe local, carrier-density-dependent properties in graphene, we have carried out atomically resolved scanning tunnelling spectroscopy measurements on mechanically cleaved graphene flake devices equipped with tunable back-gate electrodes. We observe an unexpected gap-like feature in the graphene tunnelling spectrum that remains pinned to the Fermi level (EF) regardless of graphene electron density. This gap is found to arise from a suppression of electronic tunnelling to graphene states near EF and a simultaneous giant enhancement of electronic tunnelling at higher energies due to a phonon-mediated inelastic channel. Phonons thus act as a ‘floodgate’ that controls the flow of tunnelling electrons in graphene. This work reveals important new tunnelling processes in gate-tunable graphitic layers.
Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry
View Paper: https://www.semanticscholar.org/paper/8d5698af330040479dfd11ec78f196c4748128c0
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Atomic and Molecular Physics, and Optics
In Materials Chemistry
Citations in the corpus
- Colloquium: Graphene spectroscopy (2014, methodology): “16For a discussion of these numerical values and comparison with graphite, see Kuzmenko et al. (2009a,c); Li et al. (2009b); and Zhang et al. (2008a).”
- Spatially resolving edge states of chiral graphene nanoribbons (2011, result): “This is very similar to the behaviour observed in the middle of large-scale graphene sheets, and is attributed to the onset of phonon-assisted inelastic electron tunnellin”
- Raman characterization of defects and dopants in graphene (2015, background): “For a thin spacer layer, like ion-gels and tunneling gaps in scanning tunneling microscopes [98, 99], the first term in equation (12) can add a significant contribution.”
- Evolution of microscopic localization in graphene in a magnetic field from scattering resonances to quantum dots (2010, methodology): “With the ability to control the charge density of Dirac fermions using an electrostatic back gate with fine resolution, which was not used in previous STS studie”
- Electronic transport in two-dimensional graphene (2010, methodology): “, 2007), they are virtually absent in all similar studies in exfoliated graphene (Ishigami et al., 2007; Stolyarova et al., 2007; Zhang et al., 2008).”