Single and Multi-Channel Carbon-based Quantum Dragons

In the coherent regime for electrical conductance measurements, two semi-infinite leads are connected to a finite nanostructure, and the nano-device conductance is calculated using the Landauer formula. Any channel $k$ that has transmission for electrons with energy $E$, ${\cal T}_k(E)$$=$$1$ contributes the conductance quantum $G_0$$=$$2e^2/h$. Any nano-device with at least one ${\cal T}_k(E)$$=$$1$ is called a quantum dragon [1]. The transmission probability ${\cal T}_{k}(E)$ can be obtained from the solution of the time-independent Schr{\"o}dinger equation. Uniform leads connected to armchair single-walled carbon nanotubes (SWCNTs) have ${\cal T}(E)$$=$$1$, while when connected to zigzag SWCNT the ${\cal T}(E)$ is less than unity. Appropriately dimerized leads connected to zigzag SWCNTs are quantum dragons, while when connected to armchair SWCNTs ${\cal T}(E)$ is less than unity [1]. We have generalized the matrix method and mapping methods of [1] in order to investigate SWCNTs that can be multi-channel quantum dragons. For example, one can use armchair SWCNT leads to connect to an armchair SWCNT to try to produce a multi-channel quantum dragon. \hfil\break [1] M.A.\ Novotny, Phys.\ Rev.\ B {\bf 90}, 165103 [14 pages] (2014).