论文标题
中心对称超导体SC $ _5 $ CO $ _4 $ _4 $ si $ _ {10} $由Muon-Spin光谱探测
Nodeless time-reversal symmetry breaking in the centrosymmetric superconductor Sc$_5$Co$_4$Si$_{10}$ probed by muon-spin spectroscopy
论文作者
论文摘要
We investigate the superconducting properties of Sc$_{5}$Co$_{4}$Si$_{10}$ using low-temperature resistivity, magnetization, heat capacity, and muon-spin rotation and relaxation ($μ$SR) measurements.我们发现SC $ _ {5} $ co $ _ {4} $ si $ _ {10} $ {type-ii}超导温度$ t_ \ mathrm {c} = 3.5（3.5（1）$ \，k，k。从横向场$μ$ $ SR光谱获得的超氟密度的温度依赖性是使用各向异性bardeen-cooper-schrieffer type $ s $ s $ s $ s $ s $ s $ s $ s-Wave Gap Symmetry建模的，该差距为$2Δ/k_ \ mathrm {b}然而，零场启动旋转弛豫不对称揭示了$ t_ \ mathrm {c} $以下自发磁场的外观，表明在超导状态下，时间反转对称性（TRS）被损坏。尽管这种行为通常与非独立或混合单线 - 三个搭配有关，但我们对金茨堡 - 兰道自由能以及密度功能理论计算的群体理论分析表明，非常常规的机制不太可能。因此，我们假设TRS破裂可能通过常规的电子过程发生。
We investigate the superconducting properties of Sc$_{5}$Co$_{4}$Si$_{10}$ using low-temperature resistivity, magnetization, heat capacity, and muon-spin rotation and relaxation ($μ$SR) measurements. We find that Sc$_{5}$Co$_{4}$Si$_{10}$ {exhibits type-II} superconductivity with a superconducting transition temperature $T_\mathrm{C}= 3.5 (1)$\,K. The temperature dependence of the superfluid density obtained from transverse-field $μ$SR spectra is best modeled using an isotropic Bardeen-Cooper-Schrieffer type $s$-wave gap symmetry with $2Δ/k_\mathrm{B}T_\mathrm{C} = 2.84(2)$. However, the zero-field muon-spin relaxation asymmetry reveals the appearance of a spontaneous magnetic field below $T_\mathrm{C}$, indicating that time-reversal symmetry (TRS) is broken in the superconducting state. Although this behavior is commonly associated with non-unitary or mixed singlet-triplet pairing, our group-theoretical analysis of the Ginzburg-Landau free energy alongside density functional theory calculations indicates that unconventional mechanisms are pretty unlikely. Therefore, we have hypothesized that TRS breaking may occur via a conventional electron-phonon process.
