Non-thermal resistive switching in Mott insulator nanowires

Resistive switching can be achieved in a Mott insulator by applying current/voltage, which triggers an insulator-metal transition (IMT). This phenomenon is key for understanding IMT physics and developing novel memory elements and brain-inspired technology. Despite this, the roles of electric field and Joule heating in the switching process remain controversial. Using nanowires of two archetypal Mott insulators—VO2 and V2O3 we unequivocally show that a purely non-thermal electrical IMT can occur in both materials. The mechanism behind this effect is identified as field-assisted carrier generation leading to a doping driven IMT. This effect can be controlled by similar means in both VO2 and V2O3, suggesting that the proposed mechanism is generally applicable to Mott insulators. The energy consumption associated with the non-thermal IMT is extremely low, rivaling that of state-of-the-art electronics and biological neurons. These findings pave the way towards highly energy-efficient applications of Mott insulators.Fil: Kalcheim, Yoav. University of California at San Diego; Estados UnidosFil: Camjayi, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: del Valle, Javier. University of California at San Diego; Estados UnidosFil: Salev, Pavel. University of California at San Diego; Estados UnidosFil: Rozenberg, Marcelo. Université Paris Sud; FranciaFil: Schuller, Ivan K.. University of California at San Diego; Estados Unido

Dynamical mean field theory of an effective three-band model for NaxCoO2

We derive an effective Hamiltonian for highly correlated t2g states centered at the Co sites of NaxCoO2. The essential ingredients of the model are an O mediated hopping, a trigonal crystal-field splitting, and on-site effective interactions derived from the exact solution of a multiorbital model in a CoO6 cluster, with parameters determined previously. The effective model is solved by dynamical mean field theory. We obtain a Fermi surface and electronic dispersion that agrees well with angle-resolved photoemission spectra. Our results also elucidate the origin of the "sinking pockets" in different doping regimes. © 2009 The American Physical Society.Fil: Bourgeois, A.. Universite Paris-sud Xi; FranciaFil: Aligia, Armando Ángel. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Rozenberg, Marcelo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentin

Impurity scattering in a strongly correlated host

This work explores a simple approximation to describe isolated impurity scattering in a strongly correlated host. The approximation combines conventional one-electron scattering theory and the Dynamic Mean-Field Theory to describe strong correlations in the host. It becomes exact in several limits, including those of very strong interactions. We study the problem for a large range of parameter strengths and focus on the case of a strongly correlated metal host near the Mott metal-insulator transition. We find interesting effects on the electronic structure at the impurity site with the appearence of bound states at frequencies that are strongly renormalized from the bare impurity potential value. However, the strength of the threshold potential for the onset of the bound states remains of the order of the bare host bandwidth, i.e. essentially unrenormalized with respect to the non-interacting case. Our results may provide useful guidance for interpretation of scanning tunneling microscopy experiments in strongly correlated systems. © Europhysics Letters Association.Fil: Lederer, P.. Universidade Federal de Pernambuco; BrasilFil: Rozenberg, Marcelo Javier. Universidad de Buenos Aires; Argentina. Universite Paris-sud Xi; . Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentin

Melting transition of an Ising glass driven by a magnetic field

The quantum critical behavior of the Ising glass in a magnetic field is investigated. We focus on the spin-glass-to-paramagnet transition of the transverse degrees of freedom in the presence of a finite longitudinal field. We use two complementary techniques, the Landau theory close to the T = 0 transition and the exact diagonalization method for finite systems. This allows us to estimate the size of the critical region and characterize various crossover regimes. An unexpectedly small energy scale on the disordered side of the critical line is found, and its possible relevance to experiments on metallic glasses is briefly discussed. © 2004 The American Physical Society.Fil: Arrachea, Liliana del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Dalidovich, D.. National High Magnetic Field Laboratory; Estados UnidosFil: Dobrosavljevi?, V.. National High Magnetic Field Laboratory; Estados UnidosFil: Rozenberg, Marcelo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentin

Mechanism of electric-pulse-induced resistance switching in manganites

We investigate the electric-pulse-induced resistance switching in manganite systems. We find a "complementarity" effect where the contact resistance of electrodes at opposite ends show variations of opposite sign and is reversible. The temperature dependence of the magnitude of the effect reveals a dramatic enhancement at a temperature T*, below the metal-insulator transition. We qualitatively capture these features with a theoretical model, providing evidence for the physical mechanism of the resistance switching. We argue that doping control of the electronic state of the oxide at the interfaces is the mechanism driving the effect. © 2007 The American Physical Society.Fil: Quintero, Mariana Beatriz. Departamento de Física, CAC, CNEA; ArgentinaFil: Levy, Pablo Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Leyva, Adelma Graciela. Comisión Nacional de Energía Atómica; ArgentinaFil: Rozenberg, Marcelo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentin

A model for non-volatile electronic memory devices with strongly correlated materials

The behavior of a model for non-volatile electronic memory devices with strongly correlated materials, was investigated. The domain structure assumed in this model is motivated from a rather universal aspect of strongly correlated perovskites such as the spatial inhomogeneity that occurs at the nanoscale. It is observed that the switching mechanism is related hysteresis in the I-V characteristics and that the hysteresis is itself related to a conjectured metal-insulator transition at the level of small domains. The results show that the domains that receive charge are subject to an 'effective doping' that may drive them across a boundary between two distinct electronic phases.Fil: Rozenberg, Marcelo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Inoue, I.H.. National Institute Of Advanced Industrial Science And Technology; Estados UnidosFil: Granados Sanchez, Maria Jimena. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentin

Challenges in materials and devices for resistive-switching-based neuromorphic computing

International audienc

Electrode-Geometry Control of the Formation of a Conductive Bridge in Oxide Resistance Switching Devices

Control of the formation of conductive bridge between the metal electrodes in planar-type resistance switching device was attempted. We demonstrated in Pt/CuO/Pt devices that, using a triangular seed electrode for soft breakdown, the position and the size of the bridge can be controlled. The decrease in the size resulted in the drastic reduction of operation voltage and current to the same level as in capacitortype stacked device. We argue that the planar-type device might have a certain advantage for future non-volatile memory application.Fil: Fujiwara, Kohei. University of Tokyo; JapónFil: Yajima, Takeshi. University of Tokyo; JapónFil: Nakamura, Yoshinobu. University of Tokyo; JapónFil: Rozenberg, Marcelo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Takagi, Hidenori. University of Tokyo; Japó

Metal-insulator transition in correlated systems: A new numerical approach

We study the Mott transition in the Hubbard model within the dynamical mean field theory approach where the density matrix renormalization group method is used to solve its self-consistent equations. The DMRG technique solves the associated impurity problem. We obtain accurate estimates of the critical values of the metal-insulator transitions. For the Hubbard model away from the particle-hole symmetric case we focus our study on the region of strong interactions and finite doping where two solutions coexist. In this region we demonstrate the capabilities of this method by obtaining the frequency-dependent optical conductivity spectra. With this algorithm, more complex models having a larger number of degrees of freedom can be considered and finite-size effects can be minimized.Fil: García, D. J.. Universidade Estadual de Campinas; BrasilFil: Miranda, E.. Universidade Estadual de Campinas; BrasilFil: Hallberg, Karen Astrid. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Rozenberg, Marcelo Javier. Université Paris Sud; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentin