Benchmarking Current-to-Voltage Amplifiers for Quantum Transport Measurements

TL;DR

This paper systematically compares four current-to-voltage amplifier designs optimized for quantum transport measurements, analyzing their sensitivity, noise, and dynamic range to guide experimental setup choices.

Contribution

It introduces a comprehensive framework for evaluating and selecting current-to-voltage amplifiers tailored for molecular electronics and break junction techniques.

Findings

Single-stage linear amplifiers offer simplicity but higher noise.

Multi-stage cascaded amplifiers improve dynamic range at the cost of complexity.

Logarithmic amplifiers provide a wide measurement range for quantum transport.

Abstract

Accurate electrical amplification is essential in molecular electronics for measuring conductance through atomic and molecular junctions, where currents often span several orders of magnitude. In this work, we present a systematic design and comparative analysis of four current-to-voltage ($I\text{--}V$) amplifier architectures: single-stage linear, series-linear, logarithmic, and multi-stage cascaded, specifically optimized for break junction (BJ) techniques, including scanning tunneling microscopy (STM-BJ) and mechanically controllable break junctions (MCBJ). Each configuration is evaluated based on sensitivity, noise performance, and dynamic range. Our results characterize the trade-offs between circuit complexity and noise, providing a robust framework and practical guidelines for selecting amplification schemes in quantum transport experiments.