How the atomic lattice and defects affects charge transport in anisotropic surfaces

原子晶格和缺陷如何影响各向异性表面中的电荷传输

• 批准号: 450162671
• 负责人: Professor Dr. Matthias Bode
• 金额: --
• 依托单位: Lehrstuhl für Experimentelle Physik II
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/450162671?language=en
• 关键词: How; atomic; lattice; defects; affects

In this project will will utilize the molecular nanoprobe (MONA) method we recently developed to investigate how charge transport is affected by the atomic lattice of single-crystalline surfaces and of metallic and non-metallic adsorbates. In the MONA method charge carriers are injected from an STM tip into the surface and detected by means of a reversible, electron-induced switching prozess of a detector molecule which is placed a few nanometer from the STM tip. Through numerous repetitions of this injection-detection process and statistical data analysis we are able to better understand local transport properties. For example, we successfully demonstrated on a 10 nm length scale that quantum-mechanical interference effects determine the transport of hot electrons in the Ag(111) surface which exhibits a characteristic, though highly isotropic surface state. Here we propose experiments on highly anisotropic surfaces. Since these surfaces host highly anisotropic constant-energy contours of the charge density we expect a striking direction-dependence of the charge transport. For example, focussing of the charge transport might be observed due to the periodic potential of the atomic lattice or due to the nesting of the corresponding constant-energy contours. The MONA technique will enable us to detect this focussing in real space on a length scale comparable to the wavelength of the contributing electronic states. Preliminary studies performed on Pd(110) indeed reveal a striking directional dependence of the molecular switching rate, thereby confirming our expectation.

在这个项目中，我们将利用我们最近开发的分子纳米探针（MONA）方法来研究单晶表面和金属和非金属吸附物的原子晶格如何影响电荷传输。在MONA方法中，载流子从STM尖端注入到表面，并通过放置在距离STM尖端几纳米处的检测器分子的可逆电子诱导开关过程进行检测。通过这种注入检测过程的多次重复和统计数据分析，我们能够更好地了解局部输运特性。例如，我们成功地证明了在10nm长度尺度上，量子力学干涉效应决定了Ag（111）表面热电子的输运，这表现出一种特征，尽管表面状态高度各向同性。在这里，我们提出在高各向异性表面上进行实验。由于这些表面具有电荷密度的高度各向异性的恒定能量轮廓，我们期望电荷输运具有显著的方向依赖性。例如，由于原子晶格的周期势或由于相应的恒能轮廓的嵌套，可以观察到电荷输运的聚焦。MONA技术将使我们能够在与贡献电子态波长相当的长度尺度上检测到真实空间中的这种聚焦。对Pd（110）进行的初步研究确实揭示了分子开关速率的显著方向依赖性，从而证实了我们的期望。