2D Weak Localization in Trilayer Ruddelsden-Popper Nickelates

Summary

By measuring quantum corrections to the magnetoconductance in single-crystal trilayer Ruddlesden-Popper nickelates Pr₄Ni₃O₁₀ and La₄Ni₃O₁₀, this study investigates their transport dimensionality, phase coherence, and scattering mechanisms. At low temperatures, negative magnetoresistance and two-dimensional weak localization (WL) signatures are observed, and the magnetoresistance scales with the perpendicular field component as a function of magnetic field orientation, indicating that in-plane electronic transport lies in the quantum diffusive regime, whereas out-of-plane transport is incoherent, with the electronic ground state being a quasi-two-dimensional disordered Fermi liquid. Despite the high atomic numbers of La/Pr and the magnetism of Ni/Pr, WL remains relatively robust, which arises from the partial cancellation of spin-orbit scattering and spin-flip scattering, as well as the spatial isolation of rare-earth ions from the NiO₂ layers. Pressurizing to 3 GPa continuously suppresses the WL features, possibly indicating a two-dimensional/three-dimensional dimensional crossover and establishing a link between the ambient-pressure normal state and the pressure-induced superconducting state.

Materials

• Pr₄Ni₃O₁₀(PNO)
• La4Ni3O10 (LNO)

Methods

• Magnetoconductivity measurements
• Magnetoresistance measurements
• Angle-dependent magnetotransport measurements
• In-plane resistivity measurements
• c-axis resistivity measurements
• Magnetic susceptibility measurements
• Isothermal magnetization measurements
• Hydrostatic pressure measurements up to 3 GPa
• High-pressure floating-zone synthesis
• Fits to 2D weak localization formalism
• Drude-type background magnetoconductivity fit

Keywords

• 2d weak localization
• weak antilocalization
• negative magnetoresistance
• quantum diffusive regime
• incoherent out of plane transport
• quasi 2d disordered fermi liquid
• 2d/3d dimensional crossover
• charge density wave
• spin density wave
• intertwined charge and spin density waves
• spin orbit scattering
• spin flip scattering
• phase coherence
• dephasing
• kondo effect
• pressure induced superconductivity
• orbital nature
• ni 3d_x2 y2 orbitals
• ni 3d₃z2 r2 orbitals

Highlights

• This is the first study, to the authors' knowledge, of quantum corrections to magnetoconductivity on single crystals of trilayer nickelates Pr₄Ni₃O₁₀ and La₄Ni₃O₁₀ at ambient pressure and under pressures up to 3 GPa.
• Weak localization, rather than antilocalization, is observed despite the high atomic numbers of La/Pr and the magnetic Ni/Pr atoms.
• The negative magnetoresistance scales with the perpendicular field component for different field orientations, ruling out an isotropic Kondo origin and confirming its 2D orbital nature.
• Similar quantum corrections in the Pr and La compounds indicate that Pr 4f moments are decoupled from ab-plane transport.
• A c-axis resistivity anomaly around 25 K in PNO marks the onset of magnetic order on the PrA rocksalt sites and is entirely absent in ab-plane transport, directly showing that in-plane transport does not probe or couple to rare-earth ions.
• The full weak-localization expression cannot reliably separate spin-orbit and spin-flip scattering rates because the fitted parameters are strongly correlated.
• The low-temperature resistivity upturn in some samples is reasonably described by rho = rho0 - beta T^1/2, similar to polycrystalline R4Ni3O10.
• The robust weak localization occurs with relatively long phase-coherence lengths in a material containing high concentrations of both magnetic and heavy ions.

Conclusions

• The study observes 2D weak localization at low temperatures in single-crystal Pr₄Ni₃O₁₀ and La₄Ni₃O₁₀, establishing 2D quantum transport characteristics, diffusive in-plane transport, and incoherent out-of-plane transport.
• The angular dependence of the magnetoresistance establishes the 2D nature and orbital origin of the effect, and the Kondo contribution is negligible in the observed phenomena.
• The unexpected weak localization in materials with high concentrations of heavy elements and magnetic moments is attributed to partial cancellation between spin-orbit and spin-flip scattering, as well as spatial isolation of rare-earth ions from the NiO₂ planes, which are largely decoupled from electron transport.
• Application of pressure up to 3 GPa continuously suppresses weak localization, potentially signaling a 2D/3D dimensional crossover and linking the ambient-pressure normal state to the high-pressure superconducting state.
• The quasi-2D transport supports models in which Ni 3d_x2-y2 orbitals dominate the low-energy physics, while the density-wave gap mainly affects Ni 3d₃z2-r2 orbitals and causes incoherent c-axis transport; under pressure the density wave is suppressed, leading to a coherent Fermi liquid with a remarkably isotropic superconducting phase.
• The electronic ground state at ambient pressure is a quasi-2D disordered Fermi liquid.

Main claims

• PNO and LNO exhibit 2D weak localization at low temperatures, evidenced by negative magnetoresistance and scaling with the perpendicular magnetic field.
  • Evidence: Negative magnetoresistance emerges below about 2 T and below 30 K,Low-field MR scales with B sin(theta) for different field orientations,The data are incompatible with the 3D formalism and are fitted by a 2D weak-localization expression
• The electronic ground state is a quasi-2D disordered Fermi liquid with quantum diffusive in-plane transport and incoherent out-of-plane transport.
  • Evidence: 2D weak-localization signatures in magnetoconductivity,c-axis resistivity far exceeds typical Mott-Ioffe-Regel estimates,Optical reflectivity and ARPES reports indicate loss of the c-axis Drude peak and incoherent c-axis charge dynamics
• Robust weak localization despite heavy and magnetic ions arises from partial cancellation of spin-orbit and spin-flip scattering and spatial isolation of rare-earth ions from the NiO₂ layers.
  • Evidence: Similar negative MR occurs in LNO without local 4f moments and in PNO with local 4f moments,Fits give H_so*/H_phi* < 9/16 and a negative H_so*,Pr 4f moments are located between NiO₂ layers, and the c-axis anomaly around 25 K is absent in ab-plane transport
• Pressure up to 3 GPa progressively suppresses the density-wave transition and weak-localization signatures.
  • Evidence: Magneto-transport measurements were performed under hydrostatic pressures up to 3 GPa,The density-wave transition and WL contribution are progressively suppressed with pressure,Overall resistivity decreases with increasing pressure
• The pressure suppression of weak localization may signal a 2D/3D dimensional crossover and an eventual pressure-driven transition to superconductivity.
  • Evidence: Data at 2-3 GPa can be fit with both 2D and 3D forms, but with high uncertainty,Pressure increases bandwidths and interlayer hopping amplitudes,Pressure-induced superconductivity has been reported in trilayer nickelates, with a remarkably isotropic superconducting state
• The quasi-2D transport supports models where Ni 3d_x2-y2 orbitals dominate in-plane low-energy physics while the density-wave gap primarily affects Ni 3d₃z2-r2 orbitals, causing incoherent c-axis transport.
  • Evidence: In-plane metallic transport is dominated by Ni 3d_x2-y2 orbitals according to ARPES and optical studies,The density-wave gap primarily affects Ni 3d₃z2-r2 orbitals,Pressure suppresses the density wave and leads to a coherent Fermi liquid with a nearly isotropic superconducting phase

Workflow

• sample_preparation — The PNO and LNO single crystals enable transport studies and comparison of magnetic versus nonmagnetic rare-earth effects.
  • Materials: Single crystals of Pr₄Ni₃O₁₀(PNO); Single crystals of La4Ni3O10 (LNO)
  • Methods: High-pressure floating-zone furnace growth; Selection of PNO samples S1-S3 and LNO samples S1-S2
  • Observations: PNO and LNO crystals show steplike anomalies near T_DW of 158 K and 135 K, respectively; PNO contains magnetic Pr ions while LNO contains nonmagnetic La ions
• transport_measurement — The magnetotransport data reveal 2D weak localization signatures in PNO and LNO.
  • Materials: PNO single crystals; LNO single crystals
  • Methods: In-plane resistivity versus temperature; c-axis resistivity versus temperature; Magnetoresistance versus magnetic field; Angle-dependent magnetotransport
  • Observations: Metallic resistivity with density-wave anomalies; Low-temperature resistivity upturn or saturation depending on sample; Negative magnetoresistance cusp below about 2 T and below 30 K; Negative MR superimposed on a small quadratic positive MR; Low-field MR scales with the perpendicular field component B sin(theta)
• magnetic_characterization — The Pr 4f moments are largely decoupled from in-plane conduction, reducing spin-flip dephasing effects.
  • Materials: PNO samples; LNO reference sample
  • Methods: Temperature-dependent susceptibility M/H; Isothermal magnetization; Curie-Weiss fitting
  • Observations: LNO susceptibility is less than about 1 percent of PNO; PNO susceptibility resembles Curie-Weiss behavior; Effective moment about 6.2 mu_B/f.u. or about 3.1 mu_B/Pr; Low-temperature deviations and scaling with H/(T+35 K); Low-temperature magnetic feature suppressed in a 2 T field
• pressure_magnetotransport — Pressure suppresses weak localization, consistent with an approach to a 2D/3D dimensional crossover.
  • Materials: PNO sample S3
  • Methods: Hydrostatic-pressure magnetotransport; Magnetoresistance under pressure
  • Observations: Overall resistivity decreases with increasing pressure; Density-wave transition and weak-localization contribution are progressively suppressed; Data at 2-3 GPa can be fit with both 2D and 3D forms with high uncertainty
• data_analysis — The data are quantitatively consistent with 2D weak localization, weak spin-orbit scattering, and partial cancellation of spin-orbit and spin-flip effects.
  • Materials: MR data for PNO and LNO
  • Methods: Fit to the 2D weak-localization quantum correction expression; Use of simplified effective dephasing field H_phi; Inclusion of a quadratic Drude-like background MR; Extraction of phase coherence length; Angular scaling analysis
  • Observations: 2D weak-localization expression fits the data well; H_phi* is about 0.03 T at 2 K; 1/l_phi² follows approximately T¹.1 for PNO and T⁰.9 for LNO above about 8 K; H_so*/H_phi* < 9/16 and H_so* is negative; Full fits for H_so* are unreliable due to strong parameter correlation
• interpretation — The ambient-pressure normal state is a quasi-2D disordered Fermi liquid, and weak-localization suppression provides a link to the pressure-induced superconducting state.
  • Materials: PNO and LNO transport data; Literature optical, ARPES, and high-pressure superconductivity results
  • Methods: Comparison with optical conductivity and ARPES reports; Orbital-selective transport interpretation
  • Observations: In-plane transport is quantum diffusive while c-axis transport is incoherent; Density-wave order affects Ni 3d₃z2-r2 orbitals and promotes c-axis incoherence; Pressure suppresses the density wave and restores interlayer coherence; Pressure-induced superconducting state is remarkably isotropic