Scanning tunneling spectroscopy of molecules on insulating films.
Scanning tunneling spectroscopy of molecules on insulating films.
复制标题
绝缘膜上分子的扫描隧道光谱。
作者：
J. Repp;G. Meyer
金属衬底上的超薄绝缘膜是利用扫描隧道显微镜（STM）研究弱耦合极限下电子输运性质的独特系统。薄膜提供的电子去耦允许直接对未受干扰的分子轨道进行成像，正如在单个并五苯分子的情况下所证明的那样。在极性绝缘体中，吸附物上的电子态与光学声子之间的耦合有两个重要的意义：由于绝缘体的存在，共振隧穿进入分子的电子态所产生的电导谱中的峰显着加宽。第二，极性绝缘体中的离子弛豫可能导致原子和分子中有趣的电荷双稳态。基于STM的分子操纵已被用于形成金属-有机络合物以及切换单个游离碱萘分子内腔中两个氢原子的位置。
Ultrathin insulating films on metal substrates are unique systems for using a scanning tunneling microscope (STM) to study the electron transport properties in the weak-coupling limit. The electronic decoupling provided by the films allows the direct imaging of the unperturbed molecular orbitals, as will be demonstrated in the case of individual pentacene molecules. The coupling between electronic states localized on the adsorbate and optical phonons in a polar insulator has two important implications: Peaks in conductance spectra resulting from resonant tunneling into electronic states of the molecules are significantly broadened by the presence of the insulator. Second, the ionic relaxations in a polar insulator may lead to an interesting charge bistability in atoms and molecules. STM-based molecular manipulation has been used to form a metallo-organic complex as well as to switch the position of the two hydrogen atoms in the inner cavity of single free-base naphthalocyanine molecules.