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Kazim S, Mastrippolito D, Moras P, Jugovac M, Klimczuk T, Ali M, Ottaviano L, Gunnella R. Synchrotron radiation photoemission spectroscopy of the oxygen modified CrCl 3 surface. Phys Chem Chem Phys 2023; 25:3806-3814. [PMID: 36645158 DOI: 10.1039/d2cp04586a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We investigate the experimentally challenging CrCl3 surface by photon energy dependent photoemission (PE). The core and valence electrons after cleavage of a single crystal, either in a ultra-high vacuum (UHV) or in air, are studied by keeping the samples at 150 °C, aiming at confirming the atomic composition with respect to the expected bulk atomic structure. A common spectroscopic denominator revealed by data is the presence of a stable, but only partially ordered Cl-O-Cr surface. The electronic core levels (Cl 2p, Cr 2p and 3p), the latter ones of cumbersome component determination, allowed us to quantify the electron charge transfer to the Cr atom as a net result of this modification and the increased exchange interaction between metal and ligand atoms. In particular, the analysis of multiplet components by the CMT4XPS code evidenced the charge transfer to be favored, and similarly the reduced crystal field due to the established polarization field. Though it is often claimed that a significant amount of Cl and Cr atomic vacancies has to be included, such a possibility can be excluded on the basis of the sign and the importance of the shift in the binding energy of core level electrons. The present methodological approach can be of great impact to quantify the structure of ordered sub-oxide phases occurring in mono or bi-layer Cr trihalides.
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Affiliation(s)
- S Kazim
- School of Science and Technology Physics Section University of Camerino, Via Madonna delle Carceri 9, 62032 Camerino, MC, Italy.
| | - D Mastrippolito
- Dipartimento di Scienze Fisiche e Chimiche (DSFC), Università degli Studi dell'Aquila, Via Vetoio 10, 67100 L'Aquila, Italy
| | - P Moras
- Istituto di Struttura della Materia-CNR (ISM-CNR), S.S. 14, Km 163,5, 34149 Trieste, Italy
| | - M Jugovac
- Istituto di Struttura della Materia-CNR (ISM-CNR), S.S. 14, Km 163,5, 34149 Trieste, Italy
| | - T Klimczuk
- Faculty of Applied Physics and Mathematics, and Advanced Materials Centre, Gdansk University of Technology, ul. Narutowicza 11/12, 80-233 Gdansk, Poland
| | - M Ali
- Dipartimento di Scienze Fisiche e Chimiche (DSFC), Università degli Studi dell'Aquila, Via Vetoio 10, 67100 L'Aquila, Italy.,Department of Physics, Division of Science and Technology, University of Education Lahore, Jauharabad Campus, Pakistan
| | - L Ottaviano
- Dipartimento di Scienze Fisiche e Chimiche (DSFC), Università degli Studi dell'Aquila, Via Vetoio 10, 67100 L'Aquila, Italy.,CNR-SPIN UoS L' Aquila, Via Vetoio 10, 67100 L'Aquila, Italy
| | - R Gunnella
- School of Science and Technology Physics Section University of Camerino, Via Madonna delle Carceri 9, 62032 Camerino, MC, Italy. .,INFN-Sez. Perugia, Via Pascoli Perugia, Italy
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Deng H, Zhang C, Liang W, Zhang XX, Luo SN. Hot carrier dynamics of BiTeI with large Rashba spin splitting. RSC Adv 2022; 12:16479-16485. [PMID: 35754880 PMCID: PMC9167645 DOI: 10.1039/d2ra01978g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 05/13/2022] [Indexed: 11/21/2022] Open
Abstract
We present a time-resolved ultrafast optical spectroscopy study on BiTeI, a noncentrosymmetric semiconductor with large spin–orbit splitting.
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Affiliation(s)
- Hongze Deng
- The Peac Institute of Multiscale Sciences, Chengdu, Sichuan, People's Republic of China
| | - Chenhui Zhang
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Weizheng Liang
- The Peac Institute of Multiscale Sciences, Chengdu, Sichuan, People's Republic of China
| | - Xi-Xiang Zhang
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Sheng-Nian Luo
- School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan, People's Republic of China
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Kazim S, Gunnella R, Zannotti M, Giovannetti R, Klimczuk T, Ottaviano L. Determination of the refractive index and wavelength-dependent optical properties of few-layer CrCl 3 within the Fresnel formalism. J Microsc 2021; 283:145-150. [PMID: 33864639 PMCID: PMC8359837 DOI: 10.1111/jmi.13015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 04/11/2021] [Indexed: 11/28/2022]
Abstract
Based on previous reports on the optical microscopy contrast of mechanically exfoliated few layer CrCl3 transferred on 285 nm and 270 nm SiO2 on Si(100), we focus on the experimental determination of an effective mean complex refractive index via a fitting analysis based on the Fresnel equations formalism. Accordingly, the layer and wavelength‐dependent absorbance and reflectance are calculated. Layer and wavelength‐dependent optical contrast curves are then evaluated demonstrating that the contrast is significantly high only around well‐defined wavelength bands. This is validated a posteriori, by experimental UV‐Vis absorbance data. The present study aims to show the way towards the most reliable determination of thickness of the 2D material flakes during exfoliation.
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Affiliation(s)
- Shafaq Kazim
- Physics Division, School of Science and Technology, University of Camerino, Camerino, MC, Italy
| | - Roberto Gunnella
- Physics Division, School of Science and Technology, University of Camerino, Camerino, MC, Italy
| | - Marco Zannotti
- Department of Chemistry, School of Science and Technology, University of Camerino, Camerino, MC, Italy
| | - Rita Giovannetti
- Department of Chemistry, School of Science and Technology, University of Camerino, Camerino, MC, Italy
| | - Tomasz Klimczuk
- Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Gdansk, Poland
| | - Luca Ottaviano
- Dipartimento di Scienze Fisiche e Chimiche (DSFC), Università degli Studi dell'Aquila, L'Aquila, Italy.,CNR-SPIN UoS L'Aquila, L'Aquila, Via Vetoio 10 67100, Italy
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