Department of Physics, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong 999077, China.
Department of Physics, Kobe University, Kobe 658-8530, Japan.
Nat Commun. 2017 Jun 5;8:15358. doi: 10.1038/ncomms15358.
In conventional metals, modification of electron trajectories under magnetic field gives rise to a magnetoresistance that varies quadratically at low field, followed by a saturation at high field for closed orbits on the Fermi surface. Deviations from the conventional behaviour, for example, the observation of a linear magnetoresistance, or a non-saturating magnetoresistance, have been attributed to exotic electron scattering mechanisms. Recently, linear magnetoresistance has been observed in many Dirac materials, in which the electron-electron correlation is relatively weak. The strongly correlated helimagnet CrAs undergoes a quantum phase transition to a nonmagnetic superconductor under pressure. Here we observe, near the magnetic instability, a large and non-saturating quasilinear magnetoresistance from the upper critical field to 14 T at low temperatures. We show that the quasilinear magnetoresistance may arise from an intricate interplay between a nontrivial band crossing protected by nonsymmorphic crystal symmetry and strong magnetic fluctuations.
在常规金属中，磁场下电子轨迹的改变会导致磁阻在低场下呈二次方变化，随后在费米面闭合轨道上的高场下饱和。偏离常规行为的现象，例如观察到线性磁阻或非饱和磁阻，归因于奇异的电子散射机制。最近，在许多狄拉克材料中观察到了线性磁阻，其中电子-电子相关性相对较弱。强关联的手性磁体 CrAs 在压力下经历量子相变到非磁性超导体。在这里，我们在磁不稳定性附近观察到了从上临界场到 14 T 的低温下大且非饱和的准线性磁阻。我们表明，准线性磁阻可能源于非对称晶体对称性保护的非平凡能带交叉和强磁涨落之间的复杂相互作用。
