Time reversal symmetry breaking and $d$-wave superconductivity of triple-point fermions
Time reversal symmetry breaking and $d$-wave superconductivity of triple-point fermions
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DOI：
10.1103/physrevb.104.134512
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发表时间：
2021-05
期刊：
影响因子：
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通讯作者：
S. Mandal;J. Link;I. Herbut
中科院分区：
文献类型：
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作者：
S. Mandal;J. Link;I. Herbut
本文研究了手性自旋为1/2的三点费米子的三维半金属中复数张量（d波）超导序的可能性，这些费米子的有效轨道角动量为L = 1，由三个能带的交叉引起。保留动量的前三个最低阶项并假设旋转对称，我们表明所得到的平均场d波基态打破了时间反转对称，但随后关键取决于哈密顿量中两个二次项的系数。有限化学势下的相图显示了“循环”超导态和“铁磁”超导态，由磁化强度的平均值来区分；在前一种状态下，它是最小的(0)，而在后一种状态下，它是最大的(2)。在这两种状态下，我们都在准粒子谱中发现了迷你波戈留博夫-费米曲面，符合最近的一般论点。
We study the possibility of complex tensor (d-wave) superconducting order in three-dimensional semimetals with chiral spin-1/2 triple-point fermions, which have an effective orbital angular momentum of L = 1 arising from a crossing of three bands. Retaining the first three lowest order terms in momentum and assuming rotational symmetry we show that the resulting mean-field d-wave ground state breaks time reversal symmetry, but then depends crucially on the coefficients of the two quadratic terms in the Hamiltonian. The phase diagram at a finite chemical potential displays both the “cyclic” and the “ferromagnetic” superconducting states, distinguished by the average value of the magnetization; in the former state it is minimal (zero), whereas in the latter it is maximal (two). In both states we find mini Bogoliubov-Fermi surfaces in the quasiparticle spectrum, conforming to recent general arguments.