National High Magnetic Field Laboratory and Department of Physics, Florida State University, Tallahasse, Florida 32306, USA.
National High Magnetic Field Laboratory and Department of Physics, Florida State University, Tallahasse, Florida 32306, USA and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA.
Phys Rev Lett. 2014 Apr 11;112(14):147002. doi: 10.1103/PhysRevLett.112.147002.
Using a controlled weak-coupling renormalization group approach, we establish the mechanism of unconventional superconductivity in the vicinity of spin or charge ordered excitonic states for the case of electrons on the Bernal stacked bilayer honeycomb lattice. With one electron per site, this system, physically realized in bilayer graphene, is unstable towards a spontaneous symmetry breaking. Repulsive interactions favor excitonic order, such as a charge nematic and/or a layer antiferromagnet. We find that upon adding charge carriers to the system, the excitonic order is suppressed, and unconventional superconductivity appears in its place, before it is replaced by a Fermi liquid. We focus on firmly establishing this phenomenon using the renormalization group formalism within an idealized model with parabolic touching of conduction and valence bands.
使用受控弱耦合重整化群方法，我们建立了在自旋或电荷有序激子态附近的非常规超导机制，研究对象是在伯纳尔堆叠双层蜂窝晶格上的电子。对于每个位置一个电子，这个系统在双层石墨烯中物理实现，对自发对称性破缺是不稳定的。排斥相互作用有利于激子有序，例如电荷向列相和/或层反铁磁相。我们发现，向系统中添加载流子时，激子有序被抑制，而非传统超导出现在其位置，然后被费米液体取代。我们专注于使用重整化群形式在具有导带和价带抛物线接触的理想化模型中，牢固地确立这一现象。
