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PhysRevB.96.085430.pdf9890KbAdobe PDF見る/開く
タイトル :Three-quarter Dirac points, Landau levels, and magnetization in α-(BEDT-TTF)2I3
著者 :Kishigi, Keita
Hasegawa, Yasumasa
刊行年月日 :2017-8-22
収録雑誌名 :Physical Review B
巻 :96
開始ページ :085430-1
終了ページ :085430-23
要約(Abstract) :The energies as a function of the magnetic field (H) and the pressure are studied theoretically in the tight-binding model for the two-dimensional organic conductor α-(BEDT-TTF)2I3, in which massless Dirac fermions are realized. The effects of the uniaxial pressure (P) are studied by using the pressure-dependent hopping parameters. The system is semimetallic with the same area of an electron pocket and a hole pocket atP <3.0 kbar, where the energies (ε0D ) at the Dirac points locate below the Fermi energy (ε0F ) when H = 0. We find that at P = 2.3 kbar the Dirac cones are critically tilted. In that case a type of band crossing occurs at “three-quarter” Dirac points; i.e., the dispersion is quadratic in one direction and linear in the other three directions. We obtain magnetic field dependencies of the Landau levels (εn): εn − ε0D ∝ (nH)4/5 at P = 2.3 kbar (three-quarter Dirac points) and |εn − ε0F | ∝ (nH)2 at P = 3.0 kbar (the critical pressure for the semimetallic state). We also study the magnetization as a function of the inverse magnetic field. We obtain two types of quantum oscillations. One is the usual de Haas–van Alphen (dHvA) oscillation, and the other is the unusual dHvA-like oscillation which is seen even in the system without the Fermi surface.
URL :https://journals.aps.org/prb/abstract/10.1103/PhysRevB.96.085430
収録種別 :雑誌掲載論文
ISSN :24699950
出版社(者) :American Physical Society
権利(Rights) :©2017 American Physical Society
URI :http://hdl.handle.net/2298/38481
このアイテムの引用には次の識別子を使用してください: http://hdl.handle.net/2298/38481