论文标题
蜂窝状晶格中的半导体 - 超导向器转变与自旋极化超导相之间的连接
Connection between the semiconductor--superconductor transition and the spin-polarized superconducting phase in the honeycomb lattice
论文作者
论文摘要
蜂窝状晶格中非互动费米子的带状结构在布里渊区的角落展示了狄拉克锥。结果，此晶格中的费米子在现场吸引力的某个临界值下表现出半导体的行为，即$ u_ {c} $。但是，在$ u_ {c} $上方，可以发生超导阶段。我们讨论了半导体 - 螺旋体的跃迁与实现自旋极化超导率（所谓的SARMA相）之间的相互作用。我们表明，在没有磁场的情况下，可以通过下一新的邻居（NNN）跳跃来调整临界相互作用。此外，存在NNN跳跃的临界值，它定义了一系列参数可以出现，该参数可以出现。在弱耦合极限情况下，这种量子相变发生在NNN跳跃的绝对值等于最近邻居之间跳跃的三分之一。同样，在存在磁场的情况下，可以出现SARMA相，但只有在最初观察到半导体状态的一系列参数中。这两个方面都归因于Lifshitz的过渡，这是由NNN跳和外部磁场引起的。
The band structure of noninteracting fermions in the honeycomb lattice exhibits the Dirac cones at the corners of the Brillouin zone. As a consequence, fermions in this lattice manifest a semiconducting behavior below some critical value of the onsite attraction, $U_{c}$. However, above $U_{c}$, the superconducting phase can occur. We discuss an interplay between the semiconductor--superconductor transition and the possibility of realization of the spin-polarized superconductivity (the so-called Sarma phase). We show that the critical interaction can be tuned by the next-nearest-neighbor (NNN) hopping in the absence of the magnetic field. Moreover, a critical value of the NNN hopping exists, defining a range of parameters for which the semiconducting phase can emerge. In the weak coupling limit case, this quantum phase transition occurs for the absolute value of the NNN hopping equal to one third of the hopping between the nearest neighbors. Similarly, in the presence of the magnetic field, the Sarma phase can appear, but only in a range of parameters for which initially the semiconducting state is observed. Both of these aspects are attributed to the Lifshitz transition, which is induced by the NNN hopping as well as the external magnetic field.
