Quantum critical behavior in a graphenelike model
Quantum critical behavior in a graphenelike model
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DOI：
10.1103/physrevb.78.165423
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发表时间：
2008-06
影响因子：
3.7
通讯作者：
S. Hands;C. Strouthos
中科院分区：
文献类型：
--
作者：
S. Hands;C. Strouthos
我们提出的（2+1）维费米子场理论的基础上最近提出的一个模型的石墨烯组成的N{sub f}四分量狄拉克费米子在平面内移动，并通过瞬时库仑相互作用相互作用的数值模拟结果。在强耦合极限中，我们确定了将绝缘相与导电相分离的临界口味数N{sub fc}=4.8（2）。这种转变对应于一个量子临界点的位置，我们使用一个适合的状态方程的手征序参数来估计临界指数。接下来，我们模拟N{sub f}=2对应于真实的石墨烯，并近似定位从强耦合到弱耦合行为的转变。强相关性是明显的弱耦合制度。
We present the results of numerical simulations of a (2+1)-dimensional fermion field theory based on a recent proposal for a model of graphene consisting of N{sub f} four-component Dirac fermions moving in the plane and interacting via an instantaneous Coulomb interaction. In the strong-coupling limit we identify a critical number of flavors N{sub fc}=4.8(2) separating an insulating from a conducting phase. This transition corresponds to the location of a quantum critical point, and we use a fit to the equation of state for the chiral order parameter to estimate the critical exponents. Next we simulate N{sub f}=2 corresponding to real graphene and approximately locate a transition from strong- to weak-coupling behavior. Strong correlations are evident in the weak-coupling regime.