Heating-compensated constant-temperature tunneling measurements on stacks of Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ intrinsic junctions

TL;DR

This paper presents a method for real-time temperature monitoring and compensation in tunneling measurements of Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ intrinsic junctions, effectively reducing self-heating effects during high-bias experiments.

Contribution

The study introduces an in-situ temperature control technique using a thermally-coupled thermometer stack and PID control to mitigate self-heating in tunneling measurements.

Findings

Effective temperature compensation reduces self-heating artifacts.

Enhanced accuracy in high-bias tunneling measurements.

Method applicable to layered cuprate superconductors.

Abstract

In highly anisotropic layered cuprates such as Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ tunneling measurements on a stack of intrinsic junctions in a high-bias range are often susceptible to self-heating. In this study we monitored the temperature variation of a stack ("sample stack") of intrinsic junctions by measuring the resistance change of a nearby stack ("thermometer stack") of intrinsic junctions, which was strongly thermal-coupled to the sample stack through a common Au electrode. We then adopted a proportional-integral-derivative scheme incorporated with a substrate-holder heater to compensate the temperature variation. This in-situ temperature monitoring and controlling technique allows one to get rid of spurious tunneling effects arising from the self-heating in a high bias range.