Intermediate Precision of Single-Molecule Break-Junction Conductance: Measurement, Uncertainty Budget, and Design Rules
Year: 2026
Type: preprint
Abstract: A break-junction experiment records thousands of single-molecule junctions in one session and reports a feature of their conductance histogram as the molecule’s conductance, with an uncertainty from resampling the traces. That is a withinsession sampling figure; how far the value moves between sessions is not measured or budgeted. We measure it in ISO 5725 and GUM form on archived STM-BJ recordings of DNA:RNA hybrid duplexes with repeat sessions at identical settings. On seven single-duplex groups, each two sessions from different recording rounds or dates, the intermediate-precision standard deviation of a session’s median is a factor of 1.46 (95% interval 1.28 to 2.15). Read in recording order, the median also wanders within a session with a correlation length near a hundred traces, so resampling understates the within-session uncertainty about threefold; counted consistently, the between-session term holds 74% of a single-session variance budget, and on records of this length it cannot be separated from slow drift. Five candidate remedies, tested under pre-registration, do not remove it. The expanded uncertainty of a single-session value, a lower bound that excludes calibration terms, is a factor of 2.4; spreading a fixed number of traces over more sessions reduces it, and a design rule gives the sessions a comparison needs. Public deposits from a second laboratory show a between-occasion component and the same within-session dependence. The figures are specific to the system; the method is not.
Source: ChemRxiv
Author: Viraaj Minhas
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
Funder: University of Washington
OpenAlex ID: W7221621790