Superconducting versus semiconducting electronic ground state in chirality-specific double-wall carbon nanotubes

Abstract

By using two-loop renormalization group analysis, we explore the phase diagram with respect to the electron-phonon and Coulomb interaction strengths in the two (3,3)@(8,8) and (5,0)@(15,0) double-wall carbon nanotube systems (DWCNTs). Using estimation of the two types of coupling strengths from ab initio calculations, both systems are shown to scale to the superconducting fixed point as temperature decreases to zero. This is in contrast to the (3,3) and (5,0) single-wall carbon nanotubes, which scales to the Peierlsdistorted semiconducting ground state. While the superconducting transition temperature can be quite low in the (3,3)@(8,8) system, the (5,0)@(15,0) promises observable superconducting behavior. Our result is in support of recent experimental observation of superconductivity in DWCNTs.

Peierls-type metal-insulator transition in carbon nanostructures

“…The existence of the Peierls-type transition in nanocarbon@ZSM-5 implies a reasonably large electron-phonon coupling. Since superconductivity is another consequence of electron-phonon coupling, in our earlier theoretical works [29,30] we have found that better screening of Coulomb interaction among the electrons, which is a negative for superconductivity, can greatly suppress the Peierls transition while simultaneously enhance the superconductivity transition. As a result, our next experimental effort is along the direction of providing better Coulomb screening, with the intention to see if a superconducting ground state can be accomplished in this system.…”

Focus on nonlinear terahertz studies

“…In this respect, one should note that an electromagnetic wave with an electric field amplitude of − 3 MV cm 1 is accompanied by a magnetic field with an amplitude of 1 T. A natural object of THz studies is superconductors, since in conventional superconductors the superconducting gap is in the THz range. In this collection, there are three papers on superconductors, two on conventional [9,10] and one on high-temperature [11] superconductors.…”