Nanoscale Phase Coexistence and Percolative Quantum Transport

Abstract

We study the nanoscale phase coexistence of ferromagnetic metallic (FMM) and antiferromagnetic insulating (AFI) regions by including the effect of AF superexchange and weak disorder in the double exchange model. We use a new Monte Carlo technique, mapping on the disordered spin-fermion problem to an effective short range spin model, with self-consistently computed exchange constants. We recover `cluster coexistence' as seen earlier in exact simulation of small systems. The much larger sizes, $\sim 32\times 32$, accessible with our technique, allows us to study the cluster distribution for varying electron density, disorder, and temperature. We track the magnetic structure, obtain the density of states, with its `pseudogap' features, and, for the first time, provide a fully microscopic estimate of the resistivity in a phase coexistence regime, comparing it with the `percolation' scenario.

4 Pages, 2 column revtex, 5 figures. Final version, to appear in Phys. Rev. Lett

References in corpus (7)

• Colossal Magnetoresistant Materials: The Key Role of Phase Separation
• Explanation of Giant Cluster Coexistence in Doped Manganites and Other Compounds
• Resistivity of Mixed-Phase Manganites
• Atomic-scale images of charge ordering in a mixed-valence manganite
• The self-organised phases of manganites
• Study of Percolative Transitions with First-Order Characteristics in the Context of CMR Manganites
• Disorder Induced Cluster Formation near First Order Phase Transitions in Electronic Systems: Importance of Long-Range Coulomb Interaction

Cited by in corpus (18)

• Frustration-induced insulating chiral spin state in itinerant triangular-lattice magnets
• The Distinct Effects of Homogeneous Weak Disorder and Dilute Strong Scatterers on Phase Competetion in the Manganites
• Colossal Magnetoresistance Observed in Monte Carlo Simulations of the One- and Two-Orbital Models for Manganites
• Ambipolar gate effect and low temperature magnetoresistance of ultrathin La0.8Ca0.2MnO3 Films
• Experimental determination of the non-extensive entropic parameter $q$
• Macroscopic Degeneracy and Emergent Frustration in a Honeycomb Lattice Magnet
• Double Exchange Models: Self Consistent Renormalisation
• Study of the One- and Two-Band Models for Colossal Magnetoresistive Manganites Using the Truncated Polynomial Expansion Method
• Physical meaning and measurement of the entropic parameter $q$ in an inhomogeneous magnetic systems
• The Effect of Disorder in an Orbitally Ordered Jahn-Teller Insulator
• Disorder-induced orbital ordering in doped manganites
• Boundary Energies and the Geometry of Phase Separation in Double--Exchange Magnets
• Structural Disorder Induced Polaron Formation and Magnetic Scattering in the Disordered Holstein-Double Exchange Model
• Giant Tunneling Magnetoresistance, Glassiness, and the Energy Landscape at Nanoscale Cluster Coexistence
• Magnetic Reconstructions in B-site Doped Manganites
• Inhomogeneous Phases in a Double-Exchange Magnet with Long Range Coulomb Interactions
• Non-extensivity in magnetic systems: possible impact on Mossbauer results
• Colossal resistivity change besides magnetoresistance: an extended theoretical framework for electronic transport of manganites