Abstract We review recent studies of double-decker and triple-decker phthalocyanine (Pc) molecules adsorbed on surfaces in terms of the bonding configuration, electronic structure and spin state. The Pc molecule has been studied extensively in surface science. A Pc molecule can contain various metal atoms at the center, and the class of the molecule is called as metal phthalocyanine (MPc). If the center metal has a large radius, like as lanthanoid metals, it becomes difficult to incorporate the metal atom inside of the Pc ring. Pc ligands are placed so as to sandwich the metal atom, where the metal atom is placed out of the Pc plane. The molecule in this configuration is called as a multilayer-decker Pc molecule. After the finding that the double-decker Pc lanthanoid complex shows single-molecule magnet (SMM) behavior, it has attracted a large attention. This is partly due to a rising interest for the ‘molecular spintronics’, in which the freedoms of spin and charge of an electron are applied to the quantum process of information. SMMs represent a class of compounds in which a single molecule behaves as a magnet. The reported blocking temperature, below which a single SMM molecule works as an quantum magnet, has been increasing with the development in the molecular design and synthesis techniques of multiple-decker Pc complex. However, even the bulk properties of these molecules are promising for the use of electronic materials, the films of multi-decker Pc molecules is less studied than those for the MPc molecules. An intriguing structural property is expected for the multi-decker Pc molecules since the Pc planes are linked by metal atoms. This gives an additional degree of freedom to the rotational angle between the two Pc ligands, and they can make a wheel-like symmetric rotation. Due to a simple and well-defined structure of a multi-decker Pc complex, the molecule can be a model molecule for molecular machine studies. The multi-decker Pc molecules can provide interesting spin configuration. The center metal atom, including a lanthanoid metal of Tb, tends to be 3+ cation, while the Pc ligand to be 2− anion. This realizes two-spin system, in which spins from 4f electrons and π radical coexist. Though the spins of 4f orbitals of those molecules have been studied, the importance of the π radicals has been highlighted recently from the measurement of electronic conductance properties of these molecules. In this article, recent researches on multi-decker Pc molecules are reviewed. The manuscript is organized with groups of chapters as follows: (1) Film formation, (2) Spin of TbPc 2 film and Kondo resonance observation, (3) Rotation of double-decker Pc complex and chemical modification for spin control, (4) Device formation using double-decker Pc complex.

中文翻译：

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双层酞菁配合物：薄膜形成和自旋性能的扫描隧道显微镜研究

摘要 我们回顾了最近对吸附在表面上的双层和三层酞菁 (Pc) 分子的键合构型、电子结构和自旋状态的研究。Pc 分子已在表面科学中得到广泛研究。一个Pc分子的中心可以含有各种金属原子，这种分子的类别称为金属酞菁（MPc）。如果中心金属具有大半径，如镧系金属，则很难将金属原子结合到 Pc 环内部。放置 Pc 配体以便将金属原子夹在中间，其中金属原子位于 Pc 平面之外。这种结构的分子称为多层 Pc 分子。在发现双层 Pc 镧系元素复合物表现出单分子磁体 (SMM) 行为后，它引起了广泛的关注。这部分是由于人们对“分子自旋电子学”的兴趣日益浓厚，其中将电子的自旋和电荷自由应用于信息的量子过程。SMM 代表一类化合物，其中单个分子具有磁体的作用。随着多层 Pc 复合物分子设计和合成技术的发展，报道的封闭温度（低于该温度时单个 SMM 分子可用作量子磁铁）一直在增加。然而，即使这些分子的整体特性对电子材料的使用很有希望，多层 Pc 分子的薄膜比 MPc 分子的薄膜研究得更少。由于 Pc 平面由金属原子连接，因此多层 Pc 分子有望具有有趣的结构特性。这为两个 Pc 配体之间的旋转角提供了额外的自由度，并且它们可以进行轮状对称旋转。由于多层 Pc 复合体的简单且明确定义的结构，该分子可以成为分子机器研究的模型分子。多层 Pc 分子可以提供有趣的自旋构型。中心金属原子，包括镧系金属 Tb，往往是 3+ 阳离子，而 Pc 配体是 2- 阴离子。这实现了双自旋系统，其中来自 4f 电子的自旋和 π 自由基共存。尽管已经研究了这些分子的 4f 轨道的自旋，但最近从这些分子的电子电导特性的测量中强调了 π 自由基的重要性。本文综述了近年来多层PC分子的研究进展。