H-linear magnetoresistance in the T₂ resistivity regime of overdoped infinite-layer nickelate La₁₋ₓSrₓNiO₂

摘要

本研究对高结晶度的过掺杂无限层镍酸盐La_1-xSr_xNiO₂薄膜（x=0.20-0.24）进行了系统的磁输运测量，在高达62 T的脉冲磁场中揭示了正常态的两个显著特征：磁电阻不遵循Kohler定则，在高H/T极限下表现为H线性行为；同时，正常态电阻率在30 K以下始终呈现T²依赖关系。结果表明，在该模型非常规超导体中，H线性磁电阻与T²电阻率共存，为理解无限层镍酸盐中承载超导电性的正常基态的输运特性提供了新信息。

材料

• La_1-xSr_xNiO₂ thin films (x=0.20-0.24)

方法

• PLD
• Pulsed-field transport experiment (up to 62 T)
• Magnetotransport measurements
• X-ray diffraction

关键词

• h linear magnetoresistance
• t2 resistivity
• fermi liquid ground state
• strange metal
• kohler's rule violation
• overdoped regime
• pseudogap phase

亮点

• Demonstrates coexistence of H-linear MR and T₂ resistivity in a model unconventional superconductor.
• Provides new insights into the normal ground state transport that hosts superconductivity in infinite-layer nickelates.
• Contrasts with Nd-based counterpart which shows unconventional power laws.

结论

• The magnetoresistance does not follow Kohler's rule but exhibits H-linear behavior in the high H/T limit.
• The normal-state resistivity below 30 K consistently follows a T₂ behavior across the overdoped regime.
• There is coexistence of H-linear magnetoresistance and T₂ resistivity in overdoped LSNO.
• The results point to a possible impact of rare-earth magnetism on the ground-state transport characteristics.

主要论断

• The magnetoresistance of overdoped LSNO does not follow Kohler's rule and exhibits H-linear behavior in the high H/T limit.
  • 证据: Abstract,Full text: the magnetoresistance does not follow the Kohler's rule but exhibits a H-linear behavior in the high H/T limit.
• The normal-state resistivity below 30 K consistently follows a T₂ behavior across the overdoped regime.
  • 证据: Abstract,Full text: the normal-state ρ(T) below 30 K consistently follows a T₂ behavior across the overdoped regime.
• This coexistence of H-linear MR and T₂ resistivity is distinct from the Nd-counterpart and highlights the impact of rare-earth magnetism.
  • 证据: Full text,Section IV: Compared to its Nd-counterpart… LSNO exhibits distinct transport behavior in both its T- and H-dependence.

研究流程

• sample_preparation
  • 材料: La_1-xSr_xNiO₂; SrTiO₃ substrate; CaH₂
  • 方法: pulsed laser deposition; topotactic reduction
  • 观察: high-crystallinity thin films with x=0.20-0.24
• magnetotransport_measurement
  • 方法: four-probe resistivity; pulsed magnetic field up to 62T
  • 观察: field-induced normal state
• data_analysis
  • 方法: Kohler plot analysis; scaling analysis (MR vs H/T)
  • 观察: MR does not follow Kohler's rule; H-linear MR in high H/T limit; normal-state resistivity follows T₂ below 30K
• interpretation — Overdoped LSNO exhibits coexistence of H-linear MR and T₂ resistivity, suggesting strange-metal and Fermi-liquid features.