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Author Xiao, H.; Zhang, Z.; Xu, W.; Wang, Q.; Xiao, Y.; Ding, L.; Huang, J.; Li, H.; He, B.; Peeters, F.M. pdf  url
doi  openurl
  Title Terahertz optoelectronic properties of synthetic single crystal diamond Type A1 Journal article
  Year (down) 2023 Publication Diamond and related materials Abbreviated Journal  
  Volume 139 Issue Pages 110266-110268  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract A systematic investigation is undertaken for studying the optoelectronic properties of single crystal diamond (SCD) grown by microwave plasma chemical vapor deposition (MPCVD). It is indicated that, without intentional doping and surface treatment during the sample growth, the terahertz (THz) optical conduction in SCD is mainly affected by surface H-terminations, -OH-, O- and N-based functional groups. By using THz time-domain spectroscopy (TDS), we measure the transmittance, the complex dielectric constant and optical conductivity σ(ω) of SCD. We find that SCD does not show typical semiconductor characteristics in THz regime, where σ(ω) cannot be described rightly by the conventional Drude formula. Via fitting the real and imaginary parts of σ(ω) to the Drude-Smith formula, the ratio of the average carrier density to the effective electron mass γ = ne/m*, the electronic relaxation time τ and the electronic backscattering or localization factor can be determined optically. The temperature dependence of these parameters is examined. From the temperature dependence of γ, a metallic to semiconductor transition is observed at about T = 10 K. The temperature dependence of τ is mainly induced by electron coupling with acoustic-phonons and there is a significant effect of photon-induced electron backscattering or localization in SCD. This work demonstrates that THz TDS is a powerful technique in studying SCD which contains H-, N- and O-based bonds and has low electron density and high dc resistivity. The results obtained from this study can benefit us to gain an in-depth understanding of SCD and may provide new guidance for the application of SCD as electronic, optical and optoelectronic materials.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date 2023-08-02  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0925-9635 ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:200920 Serial 9103  
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Author Zhang, Z.; Chen, X.; Shi, X.; Hu, Y.; Huang, J.; Liu, S.; Ren, Z.; Huang, H.; Han, G.; Van Tendeloo, G.; Tian, H. pdf  doi
openurl 
  Title Morphotropic phase boundary in pure perovskite lead titanate at room temperature Type A1 Journal article
  Year (down) 2022 Publication Materials Today Nano Abbreviated Journal  
  Volume 20 Issue Pages 100275-5  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract For many decades, great efforts have been devoted to pursue a large piezoelectric response by an intelligent design of morphotropic phase boundaries (MPB) in solid solutions, where tetragonal (T) and rhombohedral (R) structures coexist. For example, classical PbZrxTi1-xO3 and Pb(Mg1/3Nb2/3)O-3-PbTiO3 single crystals demonstrate a giant piezoelectric response near MPB. However, as the end member of these solids, perovskite-structured PbTiO3 always adopts the T phase at room temperature. Here, we report a pathway to create room temperature MPB in a single-phase PbTiO3. The uniaxial stress along the c-axis drives a T-R phase transition bridged by a monoclinic (M) phase, which facilitates a polarization rotation in the monodomain PbTiO3. Meanwhile, we demonstrate that the coexistence of T and R phases at room temperature can be achieved via an extremely mismatched heterointerface system. The uniaxial pressure is proved as an efficient way to break the inherent symmetry and able to substantially tailor the phase transition temperature Tc. These findings provide new insights into MPB, offering the opportunity to explore the giant piezoelectric response in single-phase materials. (c) 2022 Elsevier Ltd. All rights reserved.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000906548600002 Publication Date 2022-10-18  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2588-8420 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 10.3 Times cited Open Access Not_Open_Access  
  Notes Approved Most recent IF: 10.3  
  Call Number UA @ admin @ c:irua:193477 Serial 7324  
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