arXiv subjects
Publications and source records attributed to O. A. Tretiakov.
We point out that a peculiar annihilation of a vortex-antovortex pair observed numerically by Hertel and Schneider [Phys. Rev. Lett. 97, 177202 (2006)] represents the formation and subsequent decay of a skyrmion.
Current switching in a double-barrier resonant tunneling structure is studied in the regime where the current-voltage characteristic exhibits intrinsic bistability, so that in a certain range of bias two different steady states of current are possible. Near the upper boundary V_{th} of the bistable region the upper current state is metastable, and because of the shot noise it eventually decays to the stable lower current state. We find the time of this switching process in strip-shaped devices, with the width small compared to the length. As the bias V is tuned away from the boundary value V_{th} of the bistable region, the mean switching time τincreases exponentially. We show that in long strips \lnτ\propto (V_{th} -V)^{5/4}, whereas in short strips \lnτ\propto (V_{th} -V)^{3/2}. The one-dimensional geometry of the problem enables us to obtain analytically exact expressions for both the exponential and the prefactor of τ. Furthermore, we show that, depending on the parameters of the system, the switching can be initiated either inside the strip, or at its ends.
Current-voltage characteristics of resonant-tunneling structures often exhibit intrinsic bistabilities. In the bistable region of the I-V curve one of the two current states is metastable. The system switches from the metastable state to the stable one at a random moment in time. The mean switching time τdepends exponentially on the bias measured from the boundary of the bistable region V_{th}. We find full expressions for τ(including prefactors) as functions of bias, sample geometry, and in-plane conductivity. Our results take universal form upon appropriate renormalization of the threshold voltage V_{th}. We also show that in large samples the switching initiates inside, at the edge, or at a corner of the sample depending on the parameters of the system.
We investigate the transport of electrons through a double-barrier resonant-tunneling structure in the regime where the current-voltage characteristics exhibit bistability. In this regime one of the states is metastable, and the system eventually switches from it to the stable state. We show that the mean switching time grows exponentially as the voltage across the device is tuned from the its boundary value into the bistable region. In samples of small area we find that the logarithm of the lifetime is proportional to the voltage (measured from its boundary value) to the 3/2 power, while in larger samples the logarithm of the lifetime is linearly proportional to the voltage.