论文标题
魔术角多层石墨烯与Pauli极限
The compliance of the upper critical field in magic-angle multilayer graphene with the Pauli limit
论文作者
论文摘要
Pauli限制场代表了基本磁场，在该磁场中，由于自旋 - 磁性库珀的破坏效果，超导状态崩溃了。 Cao等[1]报告说，魔法角扭曲的三层石墨烯（MATNG，n = 3）中的上临界场（即，超导状态崩溃的磁场）超过了该材料中的Pauli限制场。该观察被解释为违反MAT3G的Pauli限制领域的行为。最近，同一研究小组在MATNG（n = 4,5）超晶格[2]中报道了类似的结论。在这里，我们指出，Cao等[1]通过使用降低（达到弱耦合极限）的完全方程来计算Pauli限制场，电子 - 偶音介导的超导性。考虑到在同一篇论文中，Cao等人[1]报道了MATNG是强耦合的超导体，我们计算了强耦合案例的Pauli限制场，并表明MATNG中观察到的上临界场符合Pauli限制。这意味着在Moire多层石墨烯超晶格中没有违反Pauli限制领域的行为。
The Pauli limiting field represents fundamental magnetic field at which superconducting state collapses due to the spin-paramagnetic Cooper pair-breaking effect. Cao et al [1] reported that the upper critical field (i.e., the magnetic field at which the superconducting state collapses in experiment) in magic-angle twisted trilayer graphene (MATNG, N=3) in 2-3 times exceeds the Pauli limiting field in this material. This observation was interpreted as a violation of the Pauli-limiting field in MAT3G. Similar conclusions were recently reported by the same research group in MATNG (N=4,5) superlattices [2]. Here we point out that Cao et al [1] calculated the Pauli limiting field by the use of reduce (to the weak-coupling limit) full equation of the electron-phonon mediated superconductivity. Considering, that in the same paper, Cao et al [1] reported that MATNGs are strong coupled superconductors, we calculate the Pauli limiting field for strong coupled case and show that the observed upper critical fields in MATNGs comply with the Pauli limit. This implies that there is no violation of the Pauli limiting field in the Moire multilayer graphene superlattices.
