Intrinsic Defect-Induced Local Semiconducting-to-Metallic Regions Within Monolayer 1T-TiS<sub>2</sub> Displayed by First-Principles Calculations and Scanning Tunneling Microscopy
Using density functional theory (DFT) and scanning tunneling microscopy (STM), the intrinsic point defects, formation energy, and electronic structure of 1T-TiS<sub>2</sub> were investigated. Defect systems include single-atom vacancies, interstitial and adatom additions, and direct atom...
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MDPI AG
2025-03-01
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| author | P. J. Keeney P. M. Coelho J. T. Haraldsen |
| author_facet | P. J. Keeney P. M. Coelho J. T. Haraldsen |
| author_sort | P. J. Keeney |
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| description | Using density functional theory (DFT) and scanning tunneling microscopy (STM), the intrinsic point defects, formation energy, and electronic structure of 1T-TiS<sub>2</sub> were investigated. Defect systems include single-atom vacancies, interstitial and adatom additions, and direct atomic substitution. Using a collective approach for analyzing realistic systems for point defect investigation, we provide a more straightforward comparison to the experimental measurements, reproducing more realistic environmental conditions related to thin film growth. STM images are compared to computationally simulated electron density images to identify specific geometries that result from favorable point defects. DFT suggests that titanium interstitials are the most energetically favorable intrinsic defect, and sulfur vacancies are more likely to form than titanium vacancies within this realistic analysis, which is in agreement with STM data. A pristine, stoichiometric monolayer system is calculated to have a direct band gap of 0.422 eV, which varies based on local point defects. Local semiconducting-to-metallic electronic transitions are predicted to occur based on the presence of Ti interstitials. |
| format | Article |
| id | doaj-art-4ee8b187e0d34860a161dc4bf5f58ba4 |
| institution | Kabale University |
| issn | 2073-4352 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Crystals |
| spelling | doaj-art-4ee8b187e0d34860a161dc4bf5f58ba42025-08-20T03:43:26ZengMDPI AGCrystals2073-43522025-03-0115324310.3390/cryst15030243Intrinsic Defect-Induced Local Semiconducting-to-Metallic Regions Within Monolayer 1T-TiS<sub>2</sub> Displayed by First-Principles Calculations and Scanning Tunneling MicroscopyP. J. Keeney0P. M. Coelho1J. T. Haraldsen2Department of Physics, University of North Florida, Jacksonville, FL 32224, USADepartment of Physics, University of North Florida, Jacksonville, FL 32224, USADepartment of Physics, University of North Florida, Jacksonville, FL 32224, USAUsing density functional theory (DFT) and scanning tunneling microscopy (STM), the intrinsic point defects, formation energy, and electronic structure of 1T-TiS<sub>2</sub> were investigated. Defect systems include single-atom vacancies, interstitial and adatom additions, and direct atomic substitution. Using a collective approach for analyzing realistic systems for point defect investigation, we provide a more straightforward comparison to the experimental measurements, reproducing more realistic environmental conditions related to thin film growth. STM images are compared to computationally simulated electron density images to identify specific geometries that result from favorable point defects. DFT suggests that titanium interstitials are the most energetically favorable intrinsic defect, and sulfur vacancies are more likely to form than titanium vacancies within this realistic analysis, which is in agreement with STM data. A pristine, stoichiometric monolayer system is calculated to have a direct band gap of 0.422 eV, which varies based on local point defects. Local semiconducting-to-metallic electronic transitions are predicted to occur based on the presence of Ti interstitials.https://www.mdpi.com/2073-4352/15/3/243density functional theoryscanning tunneling microscopysurface defectsfirst-principles calculations |
| spellingShingle | P. J. Keeney P. M. Coelho J. T. Haraldsen Intrinsic Defect-Induced Local Semiconducting-to-Metallic Regions Within Monolayer 1T-TiS<sub>2</sub> Displayed by First-Principles Calculations and Scanning Tunneling Microscopy Crystals density functional theory scanning tunneling microscopy surface defects first-principles calculations |
| title | Intrinsic Defect-Induced Local Semiconducting-to-Metallic Regions Within Monolayer 1T-TiS<sub>2</sub> Displayed by First-Principles Calculations and Scanning Tunneling Microscopy |
| title_full | Intrinsic Defect-Induced Local Semiconducting-to-Metallic Regions Within Monolayer 1T-TiS<sub>2</sub> Displayed by First-Principles Calculations and Scanning Tunneling Microscopy |
| title_fullStr | Intrinsic Defect-Induced Local Semiconducting-to-Metallic Regions Within Monolayer 1T-TiS<sub>2</sub> Displayed by First-Principles Calculations and Scanning Tunneling Microscopy |
| title_full_unstemmed | Intrinsic Defect-Induced Local Semiconducting-to-Metallic Regions Within Monolayer 1T-TiS<sub>2</sub> Displayed by First-Principles Calculations and Scanning Tunneling Microscopy |
| title_short | Intrinsic Defect-Induced Local Semiconducting-to-Metallic Regions Within Monolayer 1T-TiS<sub>2</sub> Displayed by First-Principles Calculations and Scanning Tunneling Microscopy |
| title_sort | intrinsic defect induced local semiconducting to metallic regions within monolayer 1t tis sub 2 sub displayed by first principles calculations and scanning tunneling microscopy |
| topic | density functional theory scanning tunneling microscopy surface defects first-principles calculations |
| url | https://www.mdpi.com/2073-4352/15/3/243 |
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