Conductive Pattern Formation for Resistive Switching in Nonequilibrium Mott Insulators
* SPEAKERS
Name
Affiliation
E-mail
Jongeun Han
SUNY at BUffalo
* HOST(Applicant)
Name
Affiliation
E-mail
-
* DATE / TIME
2016-07-19, 16:00~, APCTP Headquaters
* ABSTRACT
Strong electron correlation drives phase transitions in electronic lattice. One of the prototypical phenomena is the Mott insulator transition due to strong Coulomb interaction among charge carriers. The nonequilibrium counterpart, a subset of the resistive switching behavior, involves strong resistance discontinuity in interacting lattice, controlled by static external field of 10^{2-4} V/cm. This behavior has been intensively studied in recent effort for emerging memory, and can be found in various semiconductor or transition metal oxides. There are a few empirical scenarios behind this remarkable phenomena, none of which have been confirmed from microscopic theories. One of the scenarios, the thermal scenario of resistive switching in correlated solids is theoretically investigated for the origin of discontinuous transitions and their triggering mechanism in the dissipative Hubbard model driven by electric field. We show that the continuous antiferromagnetic insulator-to-metallic transition in equilibrium becomes a discontinuous resistive transition driven by a switching electric field at a small fraction of the gap energy. Lattice orientation, impurity disorder and the device geometry contribute to the rich switching behavior of meta-stable metallic and insulating phases. Forward and backward sweep of electric field leads to hysteresis with distinctly different switching mechanisms. Due to spatially inhomogeneous nonequilibrium domains, a region of negative differential resistance (dI/dVs < 0 with I = current, Vs = bias across sample) emerges.
