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제목 PRL 110, 036804
작성자 관리자
조회수 4255 등록일시 2013-01-23 14:41

Fig : (left)Experimental configuration for the local tunneling spectroscopy, consisting of an STM tip and bilayer graphene on silicon carbide. (right) dI/dV map at -0.3V with structure model of bilayer graphene and the simultaneously acquired topographic image (inset)



Title :
Visualizing Atomic-Scale Negative Differential Resistance in Bilayer Graphene
(Physical Reveiw Letters 110, 036804 (2013))


We investigate the atomic-scale tunneling characteristics of bilayer graphene on silicon carbide using the scanning tunneling microscopy. The high-resolution tunneling spectroscopy reveals an unexpected negative differential resistance (NDR) at the Dirac energy, which spatially varies within the single unit cell of bilayer graphene. The origin of NDR is explained by two near-gap van Hove singularities emerging in the electronic spectrum of bilayer graphene under a transverse electric field, which are strongly localized on two sublattices in different layers. Furthermore, defects near the tunneling contact are found to strongly impact on NDR through the electron interference. Our result provides an atomic-level understanding of quantum tunneling in bilayer graphene, and constitutes a useful step towards graphene-based tunneling devices.

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