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By using a realist microscopic model, we study the electric and magnetic properties of the interface between a half metallic manganite and an insulator. We find that the lack of carriers at the interface debilitates the double exchange…

Materials Science · Physics 2015-06-25 Luis Brey

We demonstrate that in ferromagnetic Ga1-xMnxP exchange is mediated by holes localized in a Mn-derived band. For x<0.06, infrared absorption and photoconductivity spectra indicate the presence of a Mn impurity band which is not merged with…

Materials Science · Physics 2009-11-11 M. A. Scarpulla , B. L. Cardozo , W. M. Hlaing Oo , M. D. McCluskey , O. D. Dubon

A new mechanism is proposed to explain the colossal magnetoresistance and related phenomena. Moving electrons accompanied by Jahn-Teller phonon and spin-wave clouds may form composite polarons in ferromagnetic narrow-band manganites. The…

Strongly Correlated Electrons · Physics 2016-08-31 Liang-Jian Zou , H. Q. Lin , Qing-Qi Zheng

The paramagnetic insulator to ferromagnetic metal transition in Lanthanum manganites and the associated magnetoresistive phenomena is treated by considering the localization due to random hopping induced by slowly fluctuating spin…

Condensed Matter · Physics 2009-10-28 C. M. Varma

We have investigated the interplay between the metal-insulator transition and ferromagnetism in $({\rm III}_{1-x},{\rm Mn}_x){\rm V}$ ferromagnetic semiconductors. Our study is based on a model in which $S=5/2$ Mn local moments are…

Condensed Matter · Physics 2009-11-07 S. -R. Eric Yang , A. H. MacDonald

The 2D ferromagnetic Kondo model with classical corespins is studied for a hole doping up to x = 0.125 via unbiased Monte Carlo (MC) simulations. A canonical algorithm for finite temperatures is developed. We show that with realistic…

Strongly Correlated Electrons · Physics 2009-11-10 M. Daghofer , W. Koller , H. G. Evertz , W. von der Linden

We calculate the value of the Fr\"ohlich electron-phonon interaction in manganites, cuprates, and some other charge-transfer insulators and show that this interaction is much stronger than any relevant magnetic interaction. A polaron shift…

Strongly Correlated Electrons · Physics 2009-10-31 A. S. Alexandrov , A. M. Bratkovsky

Polarons - fermionic charge carriers bearing a strong companion lattice deformation - exhibit a natural tendency for self-localization due to the recursive interaction between electrons and the lattice. While polarons are ubiquitous in…

Studying the nature and consequences of electron-phonon interaction in manganites is an area of intense ongoing research. Here, in an attempt to model charge and orbital ordering in manganites displaying C-type antiferromaganetism, we study…

Strongly Correlated Electrons · Physics 2015-01-27 Ravindra Pankaj , Sudhakar Yarlagadda

The persistent proximity of insulating and metallic phases, a puzzling characterestic of manganites, is argued to arise from the self organization of the twofold degenerate e_g orbitals of Mn into localized Jahn-Teller(JT) polaronic levels…

Strongly Correlated Electrons · Physics 2009-11-10 T. V. Ramakrishnan , H. R. Krishnamurthy , S. R. Hassan , G. V. Pai

Motivated by the recent experiments and the wide tunability on the MoTe$_2$/WSe$_2$ moir\'{e} heterobilayer, we consider a physical model to explore the underlying physics for the interplay between the itinerant carriers and the local…

Strongly Correlated Electrons · Physics 2023-12-11 Haichen Jia , Bowen Ma , Rui Leonard Luo , Gang Chen

Using the Lanczos method in linear chains we study the double exchange model in the low concentration limit, including an antiferromagnetic super-exchange K. In the strong coupling limit we find that the ground state contains ferromagnetic…

Strongly Correlated Electrons · Physics 2009-10-31 C. D. Batista , J. Eroles , M. Avignon , B. Alascio

This work examines the effects of magnetic frustration due to competing ferromagnetic and antiferromagnetic Heisenberg interactions on the spin dynamics of the double-exchange model. When the local moments are non-colinear, a charge-density…

Strongly Correlated Electrons · Physics 2009-11-10 R. S. Fishman

We study the transition at T=0 from a ferromagnetic insulating to a ferromagnetic metallic phase in manganites as a function of hole doping using an effective low-energy model Hamiltonian proposed by us recently. The model incorporates the…

Strongly Correlated Electrons · Physics 2009-11-10 G. Venketeswara Pai , S. R. Hassan , H. R. Krishnamurthy , T. V. Ramakrishnan

Motivated by recent experiments on spin pumping from a ferromagnet into organic materials in which the charge transport is due to hopping, we study theoretically the generation and propagation of spin current in a hopping insulator. Unlike…

Mesoscale and Nanoscale Physics · Physics 2016-02-05 Z. Yue , D. A. Pesin , M. E. Raikh

I briefly survey here attempts to model the rich and strange behaviour of colossal magnetoresistance manganites, after outlining some of the phenomena observed in them, and describing the three relevant strong local interactions of the e_g…

Strongly Correlated Electrons · Physics 2009-11-13 T. V. Ramakrishnan

The exchange interaction of polaronic carriers with localized spins leads to a ferromagnetic/paramagnetic transition in doped charge-transfer insulators with strong electron-phonon coupling. The relative strength of the exchange and…

Strongly Correlated Electrons · Physics 2016-08-31 A. S. Alexandrov , A. M. Bratkovsky

Ferromagnetic (FM) manganites, a group of likely half-metallic oxides, are of special interest not only because they are a testing ground of the classical doubleexchange interaction mechanism for the colossal magnetoresistance, but also…

Strongly Correlated Electrons · Physics 2007-08-22 Jiandi Zhang , F. Ye , Hao Sha , Pengcheng Dai , J. A. Fernandez-Baca , E. W. Plummer

55Mn NMR was used to study the ferromagnetic insulating state in four different manganites. In all cases the coexistence of two types of regions possessing different NMR spectra and nuclear spin dynamics was found. In the ferromagnetic…

Strongly Correlated Electrons · Physics 2009-11-07 M. M. Savosta , V. I. Kamenev , V. A. Borodin , P. Novak , M. Marysko , J. Hejtmanek , K. Dorr , M. Sahana , A. Shames

We consider the double exchange model at very low densities. The conditions for the formation of self-trapped magnetic polarons are analyzed using an independent polaron model. The issue of phase separation in the low density region of the…

Strongly Correlated Electrons · Physics 2008-04-22 Vitor M. Pereira , J. M. B. Lopes dos Santos , Antonio H. Castro Neto