[14a-B414-1~5] THｚ赤外帯フォトニクス応用展開を志向したナノ材料科学

▲ [14a-B414-2] Terahertz Dynamics of Dirac Electrons in Bi and Bi_1-xSb_x Nano-films

〇Ikufumi KATAYAMA¹ (1.Yokohama Natl. Univ.)

キーワード：terahertz, bismuth, Dirac electrons

Strong light-matter interaction has been one of the important subjects of research in the field of optical science because it could be an ingredient for future high-speed opto-electric applications. Especially in the terahertz region, many materials, including graphene, are demonstrated to have the strong nonlinearity, and the origin is discussed in terms of Zener tunneling, carrier acceleration and impact ionization. It is, however, still difficult to systematically investigate the origin of nonlinearity because of the difficulty in changing band parameters of materials. Here, we focus on the Bi and Bi_1-xSb_x thin films with the thickness of some nanometers to investigate the terahertz nonlinear responses, because the band gap and Fermi energy can be tunable by changing the Sb concentration. These materials have narrow bandgap below 40 meV and hyperbolic band structures (Dirac electrons), which are suitable for investigating the strong interaction between light and matter in the terahertz region.