Photoexcited Hole States at the SrTiO3(001) Surface Imaged with Noncontact AFM

Fuente: arXiv
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Main Authors: Sokolovic, Igor, Ellinger, Florian, Alexander, Aji, Wrana, Dominik, Albons, Llorenc, Sreekumar, Sreehari, Schmid, Michael, Diebold, Ulrike, Reticcioli, Michele, Franchini, Cesare, Setvin, Martin
Format: Preprint
Published: 2026
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author Sokolovic, Igor
Ellinger, Florian
Alexander, Aji
Wrana, Dominik
Albons, Llorenc
Sreekumar, Sreehari
Schmid, Michael
Diebold, Ulrike
Reticcioli, Michele
Franchini, Cesare
Setvin, Martin
author_facet Sokolovic, Igor
Ellinger, Florian
Alexander, Aji
Wrana, Dominik
Albons, Llorenc
Sreekumar, Sreehari
Schmid, Michael
Diebold, Ulrike
Reticcioli, Michele
Franchini, Cesare
Setvin, Martin
contents The behaviour of excess charges in ionic lattices, such as the formation of polarons and charge trapping at defect sites, influences the physical and chemical properties of materials and translates into applications in electronics, optics, photovoltaics, and catalysis. Here we show that the bulk-terminated SrTiO3(001) surface accumulates photoexcited charges and keeps the associated photovoltage for many days at cryogenic temperatures. A combination of scanning tunneling microscopy, atomic force microscopy (STM/AFM) and Kelvin probe force microscopy (KPFM) was used to measure this photovoltage and to localize the photoexcited charges with atomic precision down to the single-quasiparticle limit. Density functional theory (DFT) shows that holes favor localization at oxygen 2p orbitals adjacent to Sr vacancies, creating long-lived trapped states. The methodology presented here provides guidelines for imaging of charges trapped in the crystal lattice using noncontact AFM.
format Preprint
id arxiv_https___arxiv_org_abs_2604_07114
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Photoexcited Hole States at the SrTiO3(001) Surface Imaged with Noncontact AFM
Sokolovic, Igor
Ellinger, Florian
Alexander, Aji
Wrana, Dominik
Albons, Llorenc
Sreekumar, Sreehari
Schmid, Michael
Diebold, Ulrike
Reticcioli, Michele
Franchini, Cesare
Setvin, Martin
Materials Science
The behaviour of excess charges in ionic lattices, such as the formation of polarons and charge trapping at defect sites, influences the physical and chemical properties of materials and translates into applications in electronics, optics, photovoltaics, and catalysis. Here we show that the bulk-terminated SrTiO3(001) surface accumulates photoexcited charges and keeps the associated photovoltage for many days at cryogenic temperatures. A combination of scanning tunneling microscopy, atomic force microscopy (STM/AFM) and Kelvin probe force microscopy (KPFM) was used to measure this photovoltage and to localize the photoexcited charges with atomic precision down to the single-quasiparticle limit. Density functional theory (DFT) shows that holes favor localization at oxygen 2p orbitals adjacent to Sr vacancies, creating long-lived trapped states. The methodology presented here provides guidelines for imaging of charges trapped in the crystal lattice using noncontact AFM.
title Photoexcited Hole States at the SrTiO3(001) Surface Imaged with Noncontact AFM
topic Materials Science
url https://arxiv.org/abs/2604.07114