Tilted anisotropic Dirac cones in quinoid-type graphene and α-(BEDT-TTF)2I3
Tilted anisotropic Dirac cones in quinoid-type graphene and α-(BEDT-TTF)2I3
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DOI：
10.1103/physrevb.78.045415
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发表时间：
2008-07-01
影响因子：
3.7
通讯作者：
Piechon, F.
中科院分区：
文献类型：
--
作者：
Goerbig, M. O.;Fuchs, J. -N.;Piechon, F.
我们研究了广义二维Weyl Hamiltonian，它可以描述机械变形石墨烯和有机化合物α-(BEDT-TTF)(2)I-3 [BEDT-TTF=双(亚乙基二硫)四硫富瓦烯]在压力下的低能特性。相关的色散通常具有倾斜的各向异性狄拉克锥的形式。当价带接触导带的狄拉克点与第一布里渊区内的晶体学高对称点不重合时，由于次近邻跳跃而产生倾斜。在半经典处理中，我们描述了强磁场中朗道能级的形成，其相对论形式让人想起石墨烯，由于狄拉克锥的倾斜而具有重整化的费米速度。这些相对论朗道能级可以通过光谱学甚至量子霍尔效应测量来实验获得，可以用作α-(BEDT-TTF)(2)I-3中狄拉克锥的直接实验验证。
We investigate a generalized two-dimensional Weyl Hamiltonian, which may describe the low-energy properties of mechanically deformed graphene and of the organic compound alpha-(BEDT-TTF)(2)I-3 [BEDT-TTF=bis(ethylenedithio)tetrathiafulvalene] under pressure. The associated dispersion has generically the form of tilted anisotropic Dirac cones. The tilt arises due to next-nearest-neighbor hopping when the Dirac points, where the valence band touches the conduction band, do not coincide with crystallographic high-symmetry points within the first Brillouin zone. Within a semiclassical treatment, we describe the formation of Landau levels in a strong magnetic field, the relativistic form of which is reminiscent of that of graphene, with a renormalized Fermi velocity due to the tilt of the Dirac cones. These relativistic Landau levels, experimentally accessible via spectroscopy or even a quantum-Hall-effect measurement, may be used as a direct experimental verification of Dirac cones in alpha-(BEDT-TTF)(2)I-3.