Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · cond-mat/0301452

Pressure-tuning of the electron-phonon coupling: the insulator to metal transition in manganites

P. Postorino·A. Congeduti·P. Dore·F. A. Gorelli·L. Ulivi·A. Sacchetti·A. Kumar·D. D. Sarma
View original source ↗Read source document ↗Export metadata ↓

Abstract

A comprehensive understanding of the physical origin of the unique magnetic and transport properties of A_(1-x)A'^xMnO_3 manganites (A = trivalent rare-earth and A' = divalent alkali-earth metal) is still far from being achieved. The complexity of these systems arises from the interplay among several competing interactions of comparable strength. Recently the electron-phonon coupling, triggered by a Jahn-Teller distortion of the MnO_6 octahedra, has been recognised to play an essential role in the insulator to metal transition and in the closely related colossal magneto-resistance. The pressure tuning of the octahedral distortion gives a unique possibility to separate the basic interactions and, at least in principle, to follow the progressive transformation of a manganite from an intermediate towards a weak electron-phonon coupling regime. Using a diamond anvil cell, temperature and pressure-dependent infrared absorption spectra of La_(0.75)Ca_(0.25)MnO_3 have been collected and, from the spectral weight analysis, the pressure dependence of the insulator to metal transition temperature T_IM has been determined for the first time up to 11.2 GPa. The T_IM(P) curve we proposed to model the present data revealed a universality character in accounting for the whole class of intermediate coupling compounds. This property can be exploited to distinguish the intermediate from the weak coupling compounds pointing out the fundamental differences between the two coupling regimes.

Explore related subjects

cond-mat.mtrl-sci

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

P. Postorino, A. Congeduti, P. Dore, F. A. Gorelli, L. Ulivi, A. Sacchetti, A. Kumar, D. D. Sarma. 2003-01-23. Pressure-tuning of the electron-phonon coupling: the insulator to metal transition in manganites. https://doi.org/10.1103/physrevlett.91.175501

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Dynamic Peach-Koehler self-force, inertia, and radiation damping of a regularized dislocation

The elastodynamic Peach-Koehler force is computed for a fully-regularized straight dislocation with isotropic core in continuum isotropic elastic elasticity, in compact forms involving partial mass or impulsion functions relative to shear and compressional waves. The force accounts for both dynamic radiation damping and inertia. The expressions are valid indifferently for subsonic or supersonic velocities. Results are compared with the case of a flat-core dislocation of the Peierls-Eshelby type, for a motion of jump from rest to constant velocity. In the steady-state limit, the Lagrangian function relevant to expressing the force in the flat-core case must be replaced by a related but different function for the regularized dislocation. However, by suitably defining the regularizing dislocation width, the steady-state limits of the force for the fully-regularized and flat-core dislocations can be matched exactly.

cond-mat.mtrl-sci↗
arXiv2026

LightPFP: A Lightweight Route to Ab Initio Accuracy at Scale

Machine learning interatomic potentials (MLIPs) bridge the gap between quantum-mechanical accuracy and scalable molecular simulations. However, a fundamental trade-off persists: universal MLIPs (u-MLIPs) offer broad transferability but are computationally expensive, whereas task-specific MLIPs (ts-MLIPs) achieve high efficiency at the expense of costly DFT training data. Here we introduce LightPFP, a data-efficient knowledge distillation framework. Instead of relying on expensive DFT calculations, LightPFP constructs a distilled ts-MLIP by using a u-MLIP to generate high-quality, material-specific training data, while employing a pre-trained lightweight model to further improve data efficiency. Across diverse material systems, LightPFP reduces model development time by approximately three orders of magnitude compared with DFT-based workflows, while maintaining DFT-level accuracy. Combined with a LAMMPS/Kokkos inference backend, LightPFP achieves more than three orders of magnitude higher inference efficiency than u-MLIP baselines while enabling simulations of systems thousands of times larger. When the teacher exhibits systematic bias, LightPFP supports few-shot precision correction using as few as 10 high-accuracy DFT configurations, as demonstrated by reproducing MgO's experimental melting point. This u-MLIP-driven distillation establishes a scalable route to high-fidelity, data-efficient MLIPs, accelerating the pace of materials discovery and design.

cond-mat.mtrl-sci↗
arXiv2026

First-order polarization process as an alternative to antiferroelectricity

Antiferroelectrics generate significant interest since their polarization versus electric field (P-E) curves show typical double-hysteresis loops appealing for various applications. Unfortunately, antiferroelectrics are rare. In magnetic compounds, magnetization versus magnetic field (M-H) curves can show analogous double hysteresis loops not only in antiferromagnets but also in systems exhibiting field-induced first-order reorientation of the magnetization through a so-called first-order magnetization process. Here, we show that appealing double-hysteresis P-E loops can also appear from an unprecedented first-order polarization process. Focusing on non-polar CaTiO3, which can be turned ferroelectric under tensile strain, we study epitaxial thin films on differently-oriented NdGaO3 substrates using a combination of theoretical and experimental techniques. We uncover that a certain configuration exhibits double-hysteresis P-E loops that we rationalize from a field-induced abrupt rotation of the polarization. Such a first-order polarization process establishes a promising alternative pathway to achieve double hysteresis P-E loops appealing for practical applications.

cond-mat.mtrl-sci↗