Dynamics of electronically phase-separated states in the double exchange model

Luo, Jing; Chern, Gia-Wei

doi:10.1103/physrevb.103.115137

Cited by 8 publications

(5 citation statements)

References 73 publications

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“…The CMR and metal-insulator transitions in manganites are therefore thought to rely on cluster-dynamics, rather than on the dynamics of atomic magnetic moments. Indeed, theories based on small FM clusters of randomly oriented magnetizations seem to provide a considerable improvement in our understanding of the CMR and the associated FM metallic state [39][40][41][42][43][44]. The origin of the insulating behavior in the PM and CO/AFM phases, however, still remains unresolved.…”

Section: Introductionmentioning

confidence: 99%

Grain-Size-Induced Collapse of Variable Range Hopping and Promotion of Ferromagnetism in Manganite La0.5Ca0.5MnO3

et al. 2022

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Among transition metal oxides, manganites have attracted significant attention because of colossal magnetoresistance (CMR)—a magnetic field-induced metal–insulator transition close to the Curie temperature. CMR is closely related to the ferromagnetic (FM) metallic phase which strongly competes with the antiferromagnetic (AFM) charge ordered (CO) phase, where conducting electrons localize and create a long range order giving rise to insulator-like behavior. One of the major open questions in manganites is the exact origin of this insulating behavior. Here we report a dc resistivity and magnetization study on manganite La1−xCaxMnO3 ceramic samples with different grain size, at the very boundary between CO/AFM insulating and FM metallic phases x=0.5. Clear signatures of variable range hopping (VRH) are discerned in resistivity, implying the disorder-induced (Anderson) localization of conducting electrons. A significant increase of disorder associated with the reduction in grain size, however, pushes the system in the opposite direction from the Anderson localization scenario, resulting in a drastic decrease of resistivity, collapse of the VRH, suppression of the CO/AFM phase and growth of an FM contribution. These contradictory results are interpreted within the standard core-shell model and recent theories of Anderson localization of interacting particles.

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Section: Introductionmentioning

confidence: 99%

Grain-Size-Induced Collapse of Variable Range Hopping and Promotion of Ferromagnetism in Manganite La0.5Ca0.5MnO3

et al. 2022

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“…Another mechanism for L ∼ t 1/3 domain-growth, proposed by Binder and Stauffer (BS) [71,72], is based on the Brownian motion and collision of the minority-phase droplets. For the single-band DE Hamiltonian studied in this work, the FM clusters, including magnetic polarons, are pretty much immobile up to temperatures close to the magnetic phase transition [68][69][70]. This indicates the BS scenario cannot produce a sustained domain growth in our case.…”

Section: J T I T 4 = " >mentioning

confidence: 91%

“…Moreover, even if some charge carriers manage to escape confinement of the emerging FM-clusters described above, they are soon transformed to relatively immobile quasi-particles called magnetic polarons [30,[65][66][67][68][69][70], some of which are highlighted in Fig. 4(b).…”

Section: J T I T 4 = " >mentioning

confidence: 99%

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Arrested phase separation in double-exchange models: machine-learning enabled large-scale simulation

Zhang,

Chern

2021

Preprint

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We present large-scale dynamical simulations of electronic phase separation in the single-band double-exchange model based on deep-learning neural-network potentials trained from small-size exact diagonalization solutions. We uncover an intriguing correlation-induced freezing behavior as doped holes are segregated from half-filled insulating background during equilibration. While the aggregation of holes is stabilized by the formation of ferromagnetic clusters through Hund's coupling between charge carriers and local magnetic moments, this stabilization also creates confining potentials for holes when antiferromagnetic spin-spin correlation is well developed in the background. The dramatically reduced mobility of the self-trapped holes prematurely disrupts further growth of the ferromagnetic clusters, leading to an arrested phase separation. Implications of our findings for phase separation dynamics in materials that exhibit colossal magnetoresistance effect are discussed.

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“…[187] The complex behavior of strongly correlated quantum systems can be visualized in real space and can be spanned into a continuous image vector space with the generative part of AE. Going one step further, a deep AE, fed by experimental SPM images and advanced simulation methods, [195,196] can make quantitative comparisons in the latent parameter space and is likely to enable a better understanding of the mechanism for the nanoscale phase composites.…”

Section: Searching For New Physics Via Unsupervised Learningmentioning

confidence: 99%

Machine Learning for Optical Scanning Probe Nanoscopy

Chen

Shabani

et al. 2022

Advanced Materials

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The ability to perform nanometer‐scale optical imaging and spectroscopy is key to deciphering the low‐energy effects in quantum materials, as well as vibrational fingerprints in planetary and extraterrestrial particles, catalytic substances, and aqueous biological samples. These tasks can be accomplished by the scattering‐type scanning near‐field optical microscopy (s‐SNOM) technique that has recently spread to many research fields and enabled notable discoveries. Herein, it is shown that the s‐SNOM, together with scanning probe research in general, can benefit in many ways from artificial‐intelligence (AI) and machine‐learning (ML) algorithms. Augmented with AI‐ and ML‐enhanced data acquisition and analysis, scanning probe optical nanoscopy is poised to become more efficient, accurate, and intelligent.

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Dynamics of electronically phase-separated states in the double exchange model

Cited by 8 publications

References 73 publications

Grain-Size-Induced Collapse of Variable Range Hopping and Promotion of Ferromagnetism in Manganite La0.5Ca0.5MnO3

Grain-Size-Induced Collapse of Variable Range Hopping and Promotion of Ferromagnetism in Manganite La0.5Ca0.5MnO3

Arrested phase separation in double-exchange models: machine-learning enabled large-scale simulation

Machine Learning for Optical Scanning Probe Nanoscopy

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