Gating a single-molecule transistor with individual atoms
Gating a single-molecule transistor with individual atoms
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DOI：
10.1038/nphys3385
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发表时间：
2015-08-01
期刊：
影响因子：
19.6
通讯作者：
Foelsch, Stefan
中科院分区：
文献类型：
--
作者：
Martinez-Blanco, Jesus;Nacci, Christophe;Foelsch, Stefan
晶体管，无论其大小如何，都依靠电栅来控制源极和漏极触点之间的电导。在原子规模的晶体管中，这种电导对单电子通过单个轨道(1，2)跳跃很敏感。分子晶体管中的单电子传输以前已经使用自上而下的门控方法来研究，例如光刻和断开结(1，3-11)。但是，这些方法不可能实现对栅极的原子精确控制--这对晶体管在最小尺寸下的作用至关重要。在这里，我们使用单个带电原子，由扫描隧道显微镜(12)操纵，为单分子晶体管创建电子门。这种程度的控制使我们能够将分子调谐到顺序单电子隧穿的区域，尽管电导间隙比之前观察到的(8，11，13，14)大一个数量级以上。这种意想不到的行为源于分子的两种不同取向构象的存在，这取决于它的电荷状态。我们的结果表明，这些电荷和构象自由度之间的强耦合导致了新的行为，超出了原子尺度晶体管中单电子传输的既定图景。
Transistors, regardless of their size, rely on electrical gates to control the conductance between source and drain contacts. In atomic-scale transistors, this conductance is sensitive to single electrons hopping via individual orbitals(1,2). Single-electron transport in molecular transistors has been previously studied using top-down approaches to gating, such as lithography and break junctions(1,3-11). But atomically precise control of the gate-which is crucial to transistor action at the smallest size scales-is not possible with these approaches. Here, we used individual charged atoms, manipulated by a scanning tunnelling microscope(12), to create the electrical gates for a single-molecule transistor. This degree of control allowed us to tune the molecule into the regime of sequential single-electron tunnelling, albeit with a conductance gap more than one order of magnitude larger than observed previously(8,11,13,14). This unexpected behaviour arises from the existence of two different orientational conformations of the molecule, depending on its charge state. Our results show that strong coupling between these charge and conformational degrees of freedom leads to new behaviour beyond the established picture of single-electron transport in atomic-scale transistors.