I – V characteristics and THz radiation properties of Bi2212 mesas

Abstract

Large mesa structures composed of intrinsic Josephson junctions (IJJs) are expected to be one of a promising source of THz electromagnetic wave. In order to study the collective dynamics in large mesas with and without the influence of self-heating effect, two types of mesa structures are fabricated. One is a double-mesa structure which enables the non-uniform bias current distribution to examine the heat-flow in large mesas. We find that the current lead geometry strongly affects the collective switching of IJJs into resistive state even if the number of IJJs in the mesas is the same. Another is a standard rectangular mesa structure used in the emission experiments. In this mesa, we observe THz radiation from IJJs biased at the low bias region, where the self-heating effect is almost negligible, on inner branches of multiple I – V structures and find that all of observed intense inner-branch emissions correspond to the same cavity resonance mode.