Giant phonon-induced conductance in scanning tunnelling spectroscopy of gate-tunable graphene

被引：407

作者：

Zhang, Yuanbo ^{[1
]}

Brar, Victor W. ^{[1
,2
]}

Wang, Feng ^{[1
]}

Girit, Caglar ^{[1
,2
]}

Yayon, Yossi ^{[1
]}

Panlasigui, Melissa ^{[1
]}

Zettl, Alex ^{[1
,2
]}

Crommie, Michael F. ^{[1
,2
]}

机构：

[1] Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA

[2] Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA

来源：

NATURE PHYSICS | 2008年 / 4卷 / 08期

关键词：

D O I：

10.1038/nphys1022

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

The honeycomb lattice of graphene is a unique two-dimensional system where the quantum mechanics of electrons is equivalent to that of relativistic Dirac fermions(1,2). Novel nanometre-scale behaviour in this material, including electronic scattering(3,4), spin-based phenomena(5) and collective excitations(6), 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 (E-F) regardless of graphene electron density. This gap is found to arise from a suppression of electronic tunnelling to graphene states near E F 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.

引用

页码：627 / 630

页数：4

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