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Nagaoka A, Kimura K, Ang AKR, Takabayashi Y, Yoshino K, Sun Q, Dou B, Wei SH, Hayashi K, Nishioka K. Direct Observation of Group-V Dopant Substitutional Defects in CdTe Single Crystals. J Am Chem Soc 2023; 145:9191-9197. [PMID: 37125455 DOI: 10.1021/jacs.3c01248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Point defect chemistry strongly affects the fundamental properties of materials and has a decisive impact on device performance. The Group-V dopant is prominent acceptor species with high hole concentration in CdTe; however, its local atomic structure is still not clear owing to difficulties in definitive measurements and discrepancies between experimental observations and theoretical models. Herein, we report on direct observation of the local structure for the As dopant in CdTe single crystals by the X-ray fluorescence holography (XFH) technique, which is a powerful tool to visualize three-dimensional atomic configurations around a specific element. The XFH result shows the As substituting on both Cd (AsCd) and Te (AsTe) sites. Although AsTe has been well known as a shallow acceptor, AsCd has not attracted much attention and been discussed so far. Our results provide new insights into point defects by expanding the experimental XFH study in combination with theoretical first-principles studies in II-VI semiconductors.
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Affiliation(s)
- Akira Nagaoka
- Research Center for Sustainable Energy & Environmental Engineering, University of Miyazaki, Miyazaki 889-2192, Japan
- Electrical and Electronic Engineering Program, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Koji Kimura
- Department of Physical Science and Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Artoni Kelvin R Ang
- Department of Physical Science and Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Yasuhiro Takabayashi
- Department of Physical Science and Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Kenji Yoshino
- Electrical and Electronic Engineering Program, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Qingde Sun
- Beijing Computational Science Research Center, Beijing 100193, China
- Hunan Provincial Key Laboratory of Flexible Electronic Materials Genome Engineering, School of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114, China
| | - Baoying Dou
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Su-Huai Wei
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Koichi Hayashi
- Department of Physical Science and Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
- Japan Synchrotron Radiation Research Institute (JASRI), Sayo, Hyogo 679-5198, Japan
| | - Kensuke Nishioka
- Research Center for Sustainable Energy & Environmental Engineering, University of Miyazaki, Miyazaki 889-2192, Japan
- Electrical and Electronic Engineering Program, University of Miyazaki, Miyazaki 889-2192, Japan
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Dietl T. Effects of Charge Dopants in Quantum Spin Hall Materials. PHYSICAL REVIEW LETTERS 2023; 130:086202. [PMID: 36898101 DOI: 10.1103/physrevlett.130.086202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
Semiconductors' sensitivity to electrostatic gating and doping accounts for their widespread use in information communication and new energy technologies. It is demonstrated quantitatively and with no adjustable parameters that the presence of paramagnetic acceptor dopants elucidates a variety of hitherto puzzling properties of two-dimensional topological semiconductors at the topological phase transition and in the regime of the quantum spin Hall effect. The concepts of resonant states, charge correlation, Coulomb gap, exchange interaction between conducting electrons and holes localized on acceptors, strong coupling limit of the Kondo effect, and bound magnetic polaron explain a short topological protection length, high hole mobilities compared with electron mobilities, and different temperature dependence of the spin Hall resistance in HgTe and (Hg,Mn)Te quantum wells.
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Affiliation(s)
- Tomasz Dietl
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw, Poland and WPI Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
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