LAUSR

Suspended metallic carbon nanotubes (m-CNTs) exhibit a remarkably large transport gap that can exceed 100 meV. Both experiment and theory suggest that strong electron-electron interactions play a crucial role in generating this electronic structure. To further understand this strongly-interacting system, we have performed electronic measurements of suspended m-CNTs with known diameter and chiral angle. Spectrally-resolved photocurrent microscopy was used to determine m-CNT structure. The room-temperature electrical characteristics of 18 individualcontacted m-CNTs were compared to their respective diameter and chiral angle. At the charge neutrality point, we observe a peak in m-CNT resistance that scales exponentially with inverse diameter. Using a thermally-activated transport model, we estimate that the transport gap is 450 meV·nm/D where D is CNT diameter. We find no correlation between the gap and the CNT chiral angle. Our results add important new constraints to theories attempting to describe the electronic structure of m-CNTs.