Abstract
Tunneling spectra of chain materials and were studied in nanoscale mesa devices. Current-voltage characteristics related to all charge density waves (CDWs) reveal universal spectra within the normally forbidden region of low , below the electronic CDW gap . The tunneling always demonstrates a threshold , followed, for both CDWs in , by a staircase fine structure. dependencies of and scale together for each CDW, while the low values correlate with the CDWs’ transition temperatures . Fine structures of CDWs perfectly coincide when scaled along . The results evidence the sequential entering of CDW vortices (dislocations) in the junction area with the tunneling current concentrated in their cores. The subgap tunneling proceeds via the phase channel: coherent phase slips at neighboring chains.
- Received 4 November 2005
DOI:https://doi.org/10.1103/PhysRevLett.96.116402
©2006 American Physical Society