The stability of current filaments in Bi2Sr2CaCu2O8 observed via luminescent thermal microscopy
Abstract
Stacks of Intrinsic Josephson Junctions (IJJs) in Bi2Sr2CaCu2O8 (Bi-2212) designed as emitters of THz-radiation are prone to strong self-heating and thermal instability due to the poor thermal conductivity and semiconducting resistivity along the c-axis. Recent theory and experimental evidence indicate a possible correlation between strong self-heating and THz power emission. Here we study the temperature distribution in stacks of IJJs using current-voltage (I-V) characteristics and direct thermal imaging. At low bias currents and at low temperature, we observe the nucleation of small hot-spots near the corners or edges of the sample. These hot-spots carry 20-30% of the entire bias current thus forming current filaments. With increasing current and at elevated temperatures the size of the hot-spot increases and it moves to the center of the sample. These observations are in excellent agreement with theoretical analysis regarding the stability of current filaments. This research was supported by the Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2015
- Bibcode:
- 2015APS..MARW11008H