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自己インターカレーション磁性半金属Cr(1+δ)Te2における熱電特性のドーピング依存性
https://doi.org/10.15102/1394.00002615
https://doi.org/10.15102/1394.00002615135e430e-c3d8-4287-95f6-c2c6c36e570e
名前 / ファイル | ライセンス | アクション |
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AtwaMohamed Full Text (85.7 MB)
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AtwaMohamed Final Exam Abstract (65.9 kB)
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Item type | 学位論文 / Thesis or Dissertation(1) | |||||||
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公開日 | 2023-01-20 | |||||||
タイトル | ||||||||
言語 | ja | |||||||
タイトル | 自己インターカレーション磁性半金属Cr(1+δ)Te2における熱電特性のドーピング依存性 | |||||||
タイトル | ||||||||
言語 | en | |||||||
タイトル | Doping Evolution of Magneto-Transport Properties in the Layered Magnetic Semimetal Cr(1+δ)Te2 | |||||||
言語 | ||||||||
言語 | eng | |||||||
資源タイプ | ||||||||
資源タイプ識別子 | http://purl.org/coar/resource_type/c_db06 | |||||||
資源タイプ | doctoral thesis | |||||||
ID登録 | ||||||||
ID登録 | 10.15102/1394.00002615 | |||||||
ID登録タイプ | JaLC | |||||||
アクセス権 | ||||||||
アクセス権 | open access | |||||||
アクセス権URI | http://purl.org/coar/access_right/c_abf2 | |||||||
著者 (英) |
Atwa, Mohamed
× Atwa, Mohamed
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抄録 | ||||||||
内容記述タイプ | Other | |||||||
内容記述 | Layered magnetic materials are important both from the fundamental perspective of understanding charge, heat, and magnetism as well as from the technological perspective of magnetically enhanced thermoelectric energy generation. Cr(1+δ)Te2 is a recently rediscovered magnetic transition metal chalcogenide (TMC) wherein controlling the fraction of Cr (δ) systematically tunes the electronic and magnetic properties of this simple binary system. This thesis reports mainly on modulating δ to tune the longitudinal thermopower Sxx for different Cr(1+δ)Te2 compositions. We show that as the fraction of doped Cr(δ) increases between δ = 0.3 and δ = 0.68, the sign of Sxx changes from positive to negative at a critical doping level of δC ≈ 0.5. The observed doping-dependent trend in the thermopower is consistent with the evolution of the semimetallic band structure in this material from ARPES, corroborating the electronic tunability of Cr(1+δ)Te2 using multiple characterization techniques. Next, an anomalous enhancement in thermoelectric response is also reported around δC, stemming from strong charge-spin coupling. Antiferromagnetic magnons are uncovered as the origin of this thermopower enhancement from analyses of the temperature-dependent magnetothermopower. This picture is further supported by the correspondence of the doping trend of the magnetothermopower with that of the magnetic anisotropy. The findings of this thesis point collectively to the critical nature of the doping level δC in magnetic semimetal Cr1+δTe2. AroundδC, near-Fermi-energy pseudogap formation and antiferromagnetic magnons combine to enhance thermoelectric energy conversion in Cr1+δTe2. | |||||||
口頭試問日 | ||||||||
2022-10-19 | ||||||||
学位授与年月日 | ||||||||
学位授与年月日 | 2022-12-31 | |||||||
学位名 | ||||||||
学位名 | Doctor of Philosophy | |||||||
学位授与番号 | ||||||||
学位授与番号 | 甲第114号 | |||||||
学位授与機関 | ||||||||
学位授与機関識別子Scheme | kakenhi | |||||||
学位授与機関識別子 | 38005 | |||||||
学位授与機関名 | Okinawa Institute of Science and Technology Graduate University | |||||||
著者版フラグ | ||||||||
出版タイプ | VoR | |||||||
出版タイプResource | http://purl.org/coar/version/c_970fb48d4fbd8a85 | |||||||
権利 | ||||||||
権利情報 | © 2022 The Author. |