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1071-專題演講-1071024-楊承山(台師大光電所)

演講活動
張貼人:李明芳公告日期:2018-09-03
Time10/24/2018 (Wed.) 14:20~16:20
SpeakerProf.楊承山(Chan-Shan Yang)
Institute of Electro-optical Science and Technology, National Taiwan Normal University
TitleExploring Dirac Electrons in Ultraclean Graphene by Applying On-Chip Terahertz Photocurrent Waveguide
AbstractMonolayer graphene is a gapless two-dimensional (2D) material with the hexagonal lattice and distinctive Dirac electronic structure. While the Fermi liquid is the canonical picture with which we understand conventional 3D metals screening long-range Coulomb interactions, the Dirac liquid can be used to theoretically describe 2D Dirac fermions near its quantum critical point (QCP). The undoped and ultraclean graphene near the QCP with marginally irrelevant Coulomb interactions is the key to understand the pure role of electron-electron interactions. In this invited talk, I will describe how we observe the preliminary proof of Dirac liquid in the ultraclean graphene system by developing and applying the extremely sensitive on-chip terahertz (THz) time-domain integrated waveguide in the past one year. We investigate the response of frequency-dependent complex photoconductivities contributed from hot electrons upon near-infrared excitation at 77°K, and show the semiconducting-to-metallic crossover by sweeping the gate voltages. According to the results of fitting the change in conductivities (Ds), the electronic temperatures and the order of electron-electron-scattering rates can be extracted and well compared to Dirac liquid predictions.
PlaceConference Room (Basement), General Hall, Gongquan Campuses, NTNU


  
最後修改時間:2018-10-22 AM 8:03

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單位簡介

本系的重點研究領域包括:凝態物理、光電與奈米科學、高能與粒子物理、軟凝態物理與生物物理、原分子光學物理、及物理科學教育等。本系前身為臺灣省立師範學院理化系物理組,成立於民國三十五年(1946年)本校創校之始。民國五十一年(1962年)本系獨立成系,民國六十三年(1974年)成立物理研究所碩士班,民國八十年(1991年)成立研究所博士班。長久以來,本系肩負著培育臺灣中等學校物理科師資的重任,但也不忘在物理學術研究上求新求進步。至今本系培育出的學術人才已有一位中研院院士及近百位中研院研究員及大學教授,各行各業的高科技人材更是不勝枚舉。民國八十三年師資培育法改制後,本系已升級為尖端學術研究、科技應用研發、及中學師資培育三者齊備的系所。

  • 國立臺灣師範大學物理系系友會
  • 系友會線上小額捐款
  • 徐有庠盃-臺灣青年學生物理辯論競賽
  • 國際物理奧林匹亞競賽
  • BOSON CLUB
  • 公用場地與儀器設施預約系統
  • 學生實習專區
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