Davydov V N
M. V. Lomonosov Moscow State University Leninsky pr. 71, app. 121 117296 Moscow Russia
RSC Adv. 2020 Jul 22;10(46):27387-27400. doi: 10.1039/d0ra04601a. eCollection 2020 Jul 21.
The origin of the Lifshitz topological transition (LTT) and the 2D nature of the LTT in graphene has been established. The peculiarities of the Lifshitz topological transitions in graphene are described at the Brillouin zone centre Γ, the zone corners K in the vicinity of the Dirac points, and at the saddle point M. A general formulation of the thermodynamics at the LTT in graphene is given. The thermodynamic characteristics of graphene are investigated at the Lifshitz topological transitions. Anomalies are found in the electron specific heat , the electron thermal coefficient of pressure, and the coefficients of electron compressibility and thermal expansion in graphene at the LTT. All the thermodynamic parameters possess the strongest singularities in graphene at the LTT near the saddle points. This opens exciting opportunities for inducing and exploring the Lifshitz topological transitions in graphene.
石墨烯中里夫希茨拓扑转变（LTT）的起源及其二维特性已得到确认。描述了石墨烯在布里渊区中心Γ、狄拉克点附近的区角K以及鞍点M处里夫希茨拓扑转变的特性。给出了石墨烯中LTT处热力学的一般公式。研究了石墨烯在里夫希茨拓扑转变时的热力学特性。发现石墨烯在LTT处的电子比热、电子压力热系数以及电子压缩系数和热膨胀系数存在异常。在鞍点附近的LTT处，石墨烯中所有的热力学参数都具有最强的奇异性。这为在石墨烯中诱导和探索里夫希茨拓扑转变开辟了令人兴奋的机会。
