Electronic and magnetic properties in monolayer/substrate interfaces of metallofullerene single molecule magnet Tb2@C79N featuring single-electron Tb-Tb bond

在分子水平上实现磁性在技术上非常有吸引力，因为它承诺极大地增加可能的存储密度，并提供许多自旋电子学的应用。给定单分子磁体(SMM)实现潜在纳米器件的先决条件是，其在块状粉末或晶体样品中表现出的磁性双稳态应保存在用作器件电极的衬底上。由于难以获得结构良好的SMM层，以及金属衬底对SMM性能的恶化影响，这些技术的实际实现受到了阻碍。将稀土元素封装在化学和热稳定的碳笼中，可以显著提高导电衬底上的SMM性能，这是在分子器件中实现SMM所必需的。Tb2deltaC79N氮富勒烯优异的SMM性能与富勒烯笼的保护作用相结合，使该分子成为改进表面SMM性能的完美候选者。在这个项目中，我们将对Tb2deltaC79N单分子膜与导电衬底界面上的磁性进行全面的研究。在扫描隧道显微镜研究了Tb2deltaC79N单分子膜的形貌之后，首先将对其在各种衬底上的气相沉积进行优化。然后用X射线磁性圆二色谱分析单分子膜的磁性。利用低温扫描隧道显微镜技术对富勒烯/衬底界面的电子性质进行了分子分辨分析。这项研究将为电动势-SMM在分子自旋电子学和量子信息处理中的潜在应用奠定基础。

Realization of magnetism on a molecular level is technologically very attractive since it promises a dramatic increase of possible storage density and offers a number of spintronics applications. A prerequisite for potential nanodevice implementation of a given single molecule magnet (SMM) is that its magnetic bistability demonstrated in bulk powder or crystal sample should be preserved on a substrate, which will serve as an electrode of a device. The practical realization of such technologies are hampered by difficulties in the obtaining of the well-structurally defined layers of SMMs, and deteriorating effect of metallic substrates on the SMM properties. Encapsulation of lanthanide species within chemically and thermally stable carbon cages opens the possibility for a dramatic improvement of the SMM performance on conducting substrates, which is required for implementation of SMMs in molecular devices. Excellent SMM properties of Tb2deltaC79N azafullerene combined with the protective role of the fullerene cage make this molecule a perfect candidate for improved on-surface SMM performance. In this project we will perform comprehensive studies of the magnetism of Tb2deltaC79N monolayers on the interface with conducting substrates. Vapor deposition of Tb2deltaC79N monolayers on various substrates will be optimized first following the scanning tunneling microscopy study of the layer morphology. Magnetic properties of the monolayers will be then analyzed by X-ray magnetic circular dichroism. Low-temperature STM technique will be used to analyze electronic properties on the fullerene/substrate interface with molecular resolution. This study will form a background for the potential use of EMF-SMMs in molecular spintronics and quantum information processing.