Electronic and Magnetic Properties of Free Radical Crystals

了解稳定自由基(Fras)与奇数个电子的强关联效应，原则上可以使我们能够设计所有的“塑料”电子材料，例如。只含有S和p元素的材料，这使得制造一系列有机半导体、磁体，甚至金属成为可能。在这种范式转变中，我们将不再用原子制造电子产品，而是用化学上复杂的分子来制造它们，这有可能带来分子电子时代。填充的惰性气体组态需要少一个电子，而惰性气体组态的电子数是偶数，这使得自由基在化学上具有很高的活性。然而，化学家们已经找到了使它们变得稳定的方法：芳香环的添加，未配对电子的离域，或者引入大体积取代基作为侧基。

Understanding the strong correlation effects in stable free radicals (FRACs) with an odd number of electrons could in principle enable us to engineer all ``plastic'' electronic materials, eg. materials containing only s and p elements, which could make it then possible to fabricate a whole range of organic semiconductors, magnets, and maybe even metals. In this paradigm shift, instead of building electronics from atoms, we would be building them from chemically complex molecules, which has the potential to give rise to the age of molecular electronics. Being one electron short of what is required for a filled noble gas configuration, which have an even number of electrons, makes the free radicals chemically highly reactive. Nevertheless, chemists have discovered ways how render them stable: the addition of aromatic rings, delocalization of the unpaired electron, or the introduction of bulky substituents as side-groups.