Fermi-liquid-to-polaron crossover. II. Double exchange and the physics of colossal magnetoresistance

Millis, A. J.; Mueller, R. O.; Shraiman, Boris I.

doi:10.1103/physrevb.54.5405

Cited by 387 publications

(302 citation statements)

References 29 publications

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“…32,33 Moving beyond the cuprates, strong e-ph and electronelectron (e-e ) interactions also are believed to be operative in a number of other systems. These include the quasi-1D edge-shared cuprates, 34 the manganites, [35][36][37] , the fullerenes, [38][39][40][41] and the rare-earth nickelates. 42,43 Thus understanding the role of the eph interaction in correlated systems is an important problem with possible implications across many materials families.…”

Section: Introductionmentioning

confidence: 99%

Determinant quantum Monte Carlo study of the two-dimensional single-band Hubbard-Holstein model

et al. 2013

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We have performed numerical studies of the Hubbard-Holstein model in two dimensions using determinant quantum Monte Carlo (DQMC). Here we present details of the method, emphasizing the treatment of the lattice degrees of freedom, and then study the filling and behavior of the fermion sign as a function of model parameters. We find a region of parameter space with large Holstein coupling where the fermion sign recovers despite large values of the Hubbard interaction. This indicates that studies of correlated polarons at finite carrier concentrations are likely accessible to DQMC simulations. We then restrict ourselves to the half-filled model and examine the evolution of the antiferromagnetic structure factor, other metrics for antiferromagnetic and charge-density-wave order, and energetics of the electronic and lattice degrees of freedom as a function of electron-phonon coupling. From this we find further evidence for a competition between charge-density-wave and antiferromagnetic order at half-filling.

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Section: Introductionmentioning

confidence: 99%

Determinant quantum Monte Carlo study of the two-dimensional single-band Hubbard-Holstein model

et al. 2013

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“…This SWT dominates the low-energy physics (< 3 eV) in manganites, and has been attributed to the appearance of Jahn-Teller (J-T) polarons as T approaches T c from below, which trap electrons hopping from Mn 3þ to Mn 4þ sites, reducing the conductivity [25,[32][33][34][35][36] (see Appendix C for more detail). The formation of this polaron peak is considered to be a signature of competition between the electron kinetic energy and the J-T lattice distortion [25]. However, this temperatureinduced SWT can be reversed by an applied B field.…”

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confidence: 99%

“…In particular, much insight into the physics of these systems has been obtained from probing large photoinduced changes in the optical conductivity between low and high frequencies [known as dynamical spectral weight transfer (DSWT)] [17][18][19][20]24], which are strongly coupled to the magnetotransport properties [25].…”

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confidence: 99%

Polaronic Transport Induced by Competing Interfacial Magnetic Order in aLa0.7Ca0.3MnO3/BiFe

Sheu

Trugman

et al. 2014

Phys. Rev. X

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Using ultrafast optical spectroscopy, we show that polaronic behavior associated with interfacial antiferromagnetic order is likely the origin of tunable magnetotransport upon switching the ferroelectric polarity in a La 0.7 Ca 0.3 MnO 3 =BiFeO 3 (LCMO/BFO) heterostructure. This is revealed through the difference in dynamic spectral weight transfer between LCMO and LCMO/BFO at low temperatures, which indicates that transport in LCMO/BFO is polaronic in nature. This polaronic feature in LCMO/BFO decreases in relatively high magnetic fields due to the increased spin alignment, while no discernible change is found in the LCMO film at low temperatures. These results thus shed new light on the intrinsic mechanisms governing magnetoelectric coupling in this heterostructure, potentially offering a new route to enhancing multiferroic functionality. The quest to achieve strong magnetoelectric coupling has driven the surge in research on multiferroic materials over the past decade. However, this has been quite difficult to accomplish using bulk materials, motivating researchers to explore other approaches, most notably the use of transition metal oxide heterostructures [1][2][3]. In these novel systems, different degrees of freedom (DOFs) (e.g., charge, spin, and orbital) are coupled at a single interface between two different oxide layers to form a new state that displays properties dramatically different from those of the individual layers [4][5][6][7][8]. Particular attention has been given to the coupling between ferromagnetic (FM), antiferromagnetic (AFM), and ferroelectric (FE) orders, as this could reveal new routes to realizing strong magnetoelectric coupling [1][2][3][9][10][11].Heterostructures consisting of manganite and multiferroic layers are particularly promising in this regard. The most extensively studied combination [2,3,9,10,12] consists of the colossal magnetoresistive manganite La 0.7 Sr 0.3 MnO 3 (LSMO) [or the similar compound La 0.7 Ca 0.3 MnO 3 (LCMO)], which is ferromagnetic below a critical temperature T c , and the canonical multiferroic BiFeO 3 (BFO), which has coexisting coupled AFM and FE phases in which the magnetization can be switched by an applied electric (E) field [13]. The combination of these materials thus has great potential for exhibiting novel phenomena by coupling different FM, AFM, and FE phases across the interface. Indeed, a new interfacial state between LSMO and BFO has been discovered experimentally and discussed theoretically [2,[14][15][16]. This state displays an exchange-bias field and magnetotransport that can be tuned by switching the FE polarization, increasing the potential for device control through interfacial coupling. However, a complete picture of the interplay between FM and AFM orders in this heterostructure has yet to be reached.Current understanding of the exchange-bias field, which arises from the interaction between FM and G-type AFM [AFMðGÞ] orders at the interface, is based on spin canting or pinning in BFO, with the assumption of negligible canting in ...

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“…Historically, their electronic states have been understood in terms of a double-exchange (DE) mechanism with localized t 2g electrons and itinerant e g electrons [2,3]. Also, it has been recognized that the e g orbitals are strongly hybridized with the oxygen p orbitals, and participate in the cooperative Jahn-Teller (JT) distortion of the MnO 6 octahedra [4,5]. The degeneracy of the e g level is lifted by the JT distortion and the resulting orbital polarization at the Mn 3+ sites can be accompanied by certain types of antiferromagnetic (AFM) spin ordering.…”

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confidence: 99%

Orbital ordering inLa0.5Sr1.5MnO4studied by model Hartree-Fock calculation

2005

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We have investigated orbital ordering in the half-doped manganite La0.5Sr1.5MnO4, which displays spin, charge and orbital ordering, by means of unrestricted Hartree-Fock calculations on the multiband p-d model. From recent experiment, it has become clear that La0.5Sr1.5MnO4 exhibits a crosstype (z 2 − x 2 /y 2 − z 2 ) orbital ordering rather than the widely believed rod-type (3x 2 − r 2 /3y 2 − r 2 ) orbital ordering. The calculation reveals that cross-type (z 2 − x 2 /y 2 − z 2 ) orbital ordering results from an effect of in-plane distortion as well as from the relatively long out-of-plane Mn-O distance. For the "Mn 4+ " site, it is shown that the elongation along the c-axis of the MnO6 octahedra leads to an anisotropic charge distribution rather than the isotropic one.PACS numbers: 71.30.+h, 71.27.+a, 71.20.Ps Perovskite-type transition-metal oxides have attracted much attention due to their wide variety of magnetic, electrical and structural properties. In particular, manganites are extensively studied because of their rich physical properties such as colossal magnetoresistance (CMR) and spin, charge and orbital ordering [1]. Historically, their electronic states have been understood in terms of a double-exchange (DE) mechanism with localized t 2g electrons and itinerant e g electrons [2,3]. Also, it has been recognized that the e g orbitals are strongly hybridized with the oxygen p orbitals, and participate in the cooperative Jahn-Teller (JT) distortion of the MnO 6 octahedra [4,5]. The degeneracy of the e g level is lifted by the JT distortion and the resulting orbital polarization at the Mn 3+ sites can be accompanied by certain types of antiferromagnetic (AFM) spin ordering. Half-doped manganites such as La 0.5 Ca 0.5 MnO 3 and La 0.5 Sr 1.5 MnO 4 exhibit a so-called CE-type AFM ordering, as shown in Fig. 1. The magnetic moments of Mn on a zigzag chain are coupled ferromagnetically, whereas the neighboring chains are coupled antiferromagnetically. The charge and orbital ordering in the single-layered perovskite La 0.5 Sr 1.5 MnO 4 and three-dimensional perovskite Nd 0.5 Sr 0.5 MnO 3 were investigated using resonant x-ray diffraction and an alternating Mn 3+ /Mn 4+ pattern were observed directly [6,7]. Mizokawa and Fujimori [8] showed that JT distortion consistent with orbital ordering plays an important role in stabilizing the CE-type AFM state by means of unrestricted Hartree-Fock calculations. The orbital ordering of the e g electrons had been thought of as a rod-type (3x 2 −r 2 /3y 2 −r 2 ) orbital ordering, as shown in Fig. 1(a). More recently, however, from the studies of liner dichroism in the Mn 2p-edge x-ray absorption [9] and resonant soft x-ray scattering at the Mn 2p edge [10] of the La 0.5 Sr 1.5 MnO 4 , where T CO ≃ 217 K and T N ≃ 110 K [11], it was demonstrated that e g electrons exhibit predominantly cross-type (z 2 − x 2 /y 2 − z 2 ) orbital ordering as shown in Fig. 1(b).In order to understand the underlying mechanism of the cross-type orbital ordering, we have studied orbital orderin...

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Fermi-liquid-to-polaron crossover. II. Double exchange and the physics of colossal magnetoresistance

Cited by 387 publications

References 29 publications

Determinant quantum Monte Carlo study of the two-dimensional single-band Hubbard-Holstein model

Determinant quantum Monte Carlo study of the two-dimensional single-band Hubbard-Holstein model

Polaronic Transport Induced by Competing Interfacial Magnetic Order in aLa0.7Ca0.3MnO3/BiFe

Orbital ordering inLa0.5Sr1.5MnO4studied by model Hartree-Fock calculation

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