Optical Stark effect of a local defect on the TiO2(110) surface

作     者：Lihuan Sun Anning Dong Jianmei Li Dong Hao Xiangqian Tang Shichao Yan Yang Guo Xinyan Shan Xinghua Lu 

作者机构：Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China School of Physical Sciences University of Chinese Academy of Sciences Beijing 100190 China School of Physical Science and Technology ShanghaiTech University Shanghai 201210 China Center for Excellence in Topological Quantum Computation Chinese Academy of Sciences Beijing 100190 China 

出 版 物：《Physical Review B》 (Phys. Rev. B)

年 卷 期：2018年第98卷第8期

页      面：081402(R)-081402(R)页

核心收录：

基　　金：National Natural Science Foundation of China, NSFC, (11774395, 91753136) Chinese Academy of Sciences, CAS, (XDB07030100) 

主　　题：Electronic transitions Laser-cluster interaction Optical pumping Stark effect Surface states 

摘      要：Probing the optical Stark effect at the single-molecule or atomic scale is crucial for understanding many photoinduced chemical and physical processes on surfaces. Here, we report a study about the optical Stark effect of single atomic defects on a TiO2(110) surface with photoassisted scanning tunneling spectroscopy. When a laser is coupled into the tunneling junction, the midgap state of the OH−O2 defects changes remarkably in differential conductance spectra. As the laser power gradually increases, the energy of the midgap state shifts away from the Fermi level with an increase in intensity and a broadening of the peak width. The observation can be explained as an optical Stark effect with the Autler-Townes formula. This large optical Stark effect is due to a tip enhancement and a strong dipole moment in the transient charged state during electron tunneling. Our study provides different aspects in exploring electron-photon interactions at the microscopic scale.