Acoustic phonons transport in a quantum waveguide embedded double defects |
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| Institution: | 1. Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, College of Physics and Microelectronics, Hunan University, Changsha 410082, China;2. Department of Physics and Electronics Information, Hunan Institute of Science and Technology, Yueyang 414004, China;3. CCAST (World Laboratory), P.O. Box 8730, Beijing 100080, China;1. Department of Physics, Sri Ramakrishna Engineering College, Coimbatore, Tamilnadu, India;2. Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Madras, Tamilnadu, India;3. Department of Nanoscience and Technology, Sri Ramakrishna Engineering College, Coimbatore, Tamilnadu, India;1. Department of Mathematics and Computer Science and Department of Chemistry and Physics, University of Arkansas at Pine Bluff, 1200 N. University Drive, Pine Bluff, AR 71601, United States;2. Department of Physics, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, United States;3. Computational Science Research Center, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, United States;4. Department of Chemical Engineering, King Abdulaziz University, Rabigh 21911, Saudi Arabia;1. Department of Physics, Faculty of Science, Minia University, El Minia, Egypt;2. Department of Physics, Faculty of Science, Cairo University, Giza, Egypt;3. Department of Laboratory Technology, College of Technological Studies, PAAET, PO Box 42325, Shuwaikh 70654, Kuwait;4. Physics Department, Faculty of Science, Jeddah University, Saudi Arabia |
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| Abstract: | By using scattering matrix method, we investigate the acoustic phonons transport in a quantum waveguide embedded double defects at low temperatures. When acoustic phonons propagate through the waveguide, the total transmission coefficient versus the reduced phonon frequency exhibits a series of resonant peaks and dips, and acoustic waves interfere with each other in the waveguide to form standing wave with particular wavelengths. In the waveguide with void defects, acoustic phonons whose frequencies approach zero can transport without scattering. The acoustic phonons propagating in the waveguide with clamped material defects, the phonons frequencies must be larger than a threshold frequency. It is also found that the thermal conductance versus temperature is qualitatively different for different types of defects. At low temperatures, when the double defects are void, the universal quantum thermal conductance and a thermal conductance plateau can be clearly observed. However, when the double defects consist of clamped material, the quantized thermal conductance disappears but a threshold temperature where mode 0 can be excited emerges. The results can provide some references in controlling thermal conductance artificially and the design of phonon devices. |
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