Theory of Manganites Exhibiting Colossal Magnetoresistance
| dc.creator | Ramakrishnan, T. V. | |
| dc.creator | Krishnamurthy, H. R. | |
| dc.creator | Hassan, S. R. | |
| dc.creator | Pai, G. Venketeswara | |
| dc.date | 2003-08-20 | |
| dc.date.accessioned | 2026-07-07T02:53:00Z | |
| dc.date.available | 2026-07-07T02:53:00Z | |
| dc.description | The electronic properties of many transition metal oxide systems require new ideas concerning the behaviour of electrons in solids for their explanation. A recent example, subsequent to that of cuprate superconductors, is of rare earth manganites doped with alkaline earths, namely $Re_{1-x}A_x MnO_3$, which exhibit colossal magnetoresistance, metal insulator transition and many other poorly understood phenomena. Here we show that the strong Jahn Teller coupling between the twofold degenerate ($d_{x^2 -y^2}$ and $d_{3z^2 -r^2}$) $e_g$ orbitals of $Mn$ and lattice modes of vibration (of the oxygen octahedra surrounding the $Mn$ ions) dynamically reorganizes the former into a set of states (which we label $\ell$) which are localized with large local lattice distortion and exponentially small intersite overlap, and another set (labelled $b$) which form a broad band. This hitherto unsuspected but microscopically inevitable $coexistence$ of radically different $\ell$ and $b$ states, and their relative energies and occupation as influenced by doping $x$, temperature $T$, local Coulomb repulsion $U$ etc., underlies the unique effects seen in manganites. We present results from strong correlation calculations using the dynamical mean-field theory which accord with a variety of observations in the orbital liquid regime (say, for $0.2\stackrel{<}\sim x \stackrel{<}\sim 0.5$).We outline extensions to include intersite $\ell$ coherence and spatial correlations/long range order. | |
| dc.description | 26pages, 4 figures, to appear as a chapter in "Colossal Magnetoresistive Manganites", ed. T. Chatterji, Kluwer Academic Publishers, Dordrecht, Netherlands (2003) | |
| dc.identifier | https://arxiv.org/abs/cond-mat/0308396 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/0308396 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/22049 | |
| dc.subject | Strongly Correlated Electrons | |
| dc.title | Theory of Manganites Exhibiting Colossal Magnetoresistance | |
| dc.type | text |