Quantized charge flow and topological phenomena in carbon nanotubes

Carbon nanotubes (CNTs) provide a robust platform for studying adiabatic charge transport, where slow, cyclic modulation of parameters, like gate voltages or external magnetic field, induces quantized current. Their quasi-one-dimensional structure, quantized conductance, and unique symmetry properties make them particularly suited for realizing controlled transport phenomena. Indeed, experimental demonstrations have shown precise, directional charge flow in CNTs, highlighting their potential as nanoscale current sources for quantum technologies. Furthermore, when coupled with topological effects, such as those arising from the Aharonov-Bohm phase or Berry curvature, CNTs offer unique opportunities to explore quantum coherence and topology-driven transport in nanosystems.

Here we propose a CNT-based Thouless adiabatic charge pump driven by mechanically induced topological phase transitions, eliminating the need for external magnetic field. Discontinuous changes in the Z-topological invariant occur at critical amplitudes of uniform mechanical deformations, coinciding with band gap closures and changes in edge states. These singular points are systematically identified across various CNT configurations. By selectively exciting two phonon modes and precisely tuning their frequency ratio, we achieve controlled adiabatic charge pumping cycles. The computed Wilson operator eigenspectra confirm the quantized flow of Wannier charge centers through the insulating bulk, offering robust evidence of quantized topological charge transport.