arXiv subjects

Andrei D. Zaikin

Publications and source records attributed to Andrei D. Zaikin.

93 records · Page 6Linked to original sources

arXiv1996

Metastable Voltage States of Coupled Josephson Junctions

We investigate a chain of capacitively coupled Josephson junctions in the regime where the charging energy dominates over the Josephson coupling, exploiting the analogy between this system and a multi-dimensional crystal. We find that the current-voltage characteristic of the current-driven chain has a staircase shape, beginning with an (insulating) non-zero voltage plateau at small currents. This behavior differs qualitatively from that of a single junction, which should show Bloch oscillations with vanishing dc voltage. The simplest system where this effect can be observed consists of three grains connected by two junctions. The theory explains the results of recent experiments on Josephson junction arrays.

cond-mat↗

arXiv1996

Parity-Affected Superconductivity in Ultrasmall Metallic Grains

We investigate the breakdown of BCS superconductivity in {\em ultra}\/small metallic grains as a function of particle size (characterized by the mean spacing $d$ between discrete electronic eigenstates), and the parity ($P$ = even/odd) of the number of electrons on the island. Assuming equally spaced levels, we solve the parity-dependent BCS gap equation for the order parameter $Δ_P (d,T)$. Both the $T=0$ critical level spacing $d_{c,P} $ and the critical temperature $T_{c,P} (d)$ at which $Δ_P = 0$ are parity dependent, and both are so much smaller in the odd than the even case that these differences should be measurable in current experiments.

cond-mat↗

arXiv1995

Parity Effects and Higher Order Tunneling in Superconducting SET Transistors

Single electron tunneling into small superconducting islands is sensitive to the gap energy of the excitations created in the process and, hence, depends on the parity of the electron number in the island. We study these effects by analyzing the kinetics of the system. Since the interplay of Coulomb blockade and parity effects leads to a blocking of single electron tunneling, higher order tunneling processes become important. This is well-established for two-electron tunneling. Here we study processes of third and fourth order. We estimate the order of magnitude for these processes and discuss their relevance for recent experiments.

cond-mat↗