2D Materials: Theory and Electronic Properties III

In this study, we address the issue of common-mode artifacts in the measurement of electronic and magnetic properties of two-dimensional (2D) materials, particularly when significant contact resistance is present. ​ Traditional four-probe configurations, while effective at eliminating resistive contributions from contact or lead resistance, can still suffer from common-mode to differential-mode signal conversion within the sample. ​ This conversion, which is in-phase with the real measurement, complicates detection and can lead to significant measurement errors such as negative resistance or smeared quantum Hall effect data. ​

We compare the performance of a traditional measurement setup with the Lake Shore M81-SSM system, which features a balanced current source and a high input impedance voltmeter. ​ Our results demonstrate that the balanced current source significantly reduces measurement errors, achieving a measured voltage much closer to the expected value compared to the traditional setup. ​ Through detailed circuit analysis, we elucidate the conditions under which common-mode artifacts become problematic and propose mitigation strategies, including the use of a balanced current source with feedback for common-mode removal. ​

Our findings suggest that the M81-SSM system is an ideal solution for accurate transport measurements in 2D materials, effectively preventing spurious signal generation due to contact resistances. ​ This work provides a critical advancement in the precise characterization of 2D materials, facilitating more reliable experimental outcomes.