2019/09/09 by Sara Mueller, Dongjoon Kim, Mueller, Sara M. +23
Engineering · Materials Science · Physics and Astronomy · #Advanced Materials Characterization Techniques #Electronic and Structural Properties of Oxides #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Semiconductor Quantum Structures and Devices
paper · pdf · doi:10.48550/arxiv.1909.04156
openalex publication_date 2019/09/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report scanning tunneling microscopy studies of individual adatoms\ndeposited on an InSb(110) surface. The adatoms can be reproducibly dropped off\nfrom the STM tip by voltage pulses, and impact tunneling into the surface by up\nto ~100x. The spatial extent and magnitude of the tunneling effect are widely\ntunable by imaging conditions such as bias voltage, set current and\nphotoillumination. We attribute the effect to occupation of a (+/0) charge\ntransition level, and switching of the associated adatom-induced band bending.\nThe effect in STM topographic images is well reproduced by transport modeling\nof filling and emptying rates as a function of the tip position. STM atomic\ncontrast and tunneling spectra are in good agreement with density functional\ntheory calculations for In adatoms. The adatom ionization effect can extend to\ndistances greater than 50 nm away, which we attribute to the low concentration\nand low binding energy of the residual donors in the undoped InSb crystal.\nThese studies demonstrate how individual atoms can be used to sensitively\ncontrol current flow in nanoscale devices.\n