Related papers: Carbon nanotubes as excitonic insulators
Excitonic insulator is a coherent electronic phase that results from the formation of a macroscopic population of bound particle-hole pairs - excitons. With only a few candidate materials known, the collective excitonic behavior is…
Electron-electron interactions and excitons in carbon nanotubes are locally measured by combining Scanning tunneling spectroscopy and optical absorption in bundles of nanotubes. The largest gap deduced from measurements at the top of the…
Recently, ultra-small-diameter Single Wall Nano Tubes with diameter of $ \sim 0.4 nm$ have been produced and many unusual properties were observed, such as superconductivity, leading to a transition temperature $T_c\sim 15^oK$, much larger…
Single-walled carbon nanotubes are strongly correlated systems with large Coulomb repulsion between two electrons occupying the same $p_z$ orbital. Within a molecular Hamiltonian appropriate for correlated $\pi$-electron systems, we show…
We report the direct observation of the spin-singlet dark excitonic state in individual single-walled carbon nanotubes through low-temperature micro-photoluminescence spectroscopy in magnetic fields. A magnetic field up to 5 T, applied…
Excitonic insulators are long-sought-after quantum materials predicted to spontaneously open a gap by the Bose condensation of bound electron-hole pairs, namely, excitons, in their ground state. Since the theoretical conjecture, extensive…
We investigate the lowest many-body excited states in carbon nanotubes by means of ab initio calculations. On the basis of these calculations and an additional theoretical analysis of the excitons, we demonstrate that the splitting between…
We study theoretically the interactions of excitonic states with surface electromagnetic modes of small-diameter (~1 nm) semiconducting single-walled carbon nanotubes. We show that these interactions can result in strong…
We investigate competing insulating phases in nearly metallic zigzag carbon nanotubes, under conditions where an applied magnetic flux approximately closes the single particle gap in one valley. Recent experiments have shown that an energy…
Many-body interactions can produce novel ground states in a condensed-matter system. For example, interacting electrons and holes can spontaneously form excitons, a neutral bound state, provided that the exciton binding energy exceeds the…
Light emission from carbon nanotubes is expected to be dominated by excitonic recombination. Here we calculate the properties of excitons in nanotubes embedded in a dielectric, for a wide range of tube radii and dielectric environments. We…
A simple method to calculate the static electric polarization of single-walled carbon nanotube (SWNT) is obtained within the second-order perturbation approximation. The results are in agreement with the previous calculation within the…
Two-dimensional (2D) moire materials provide a new solid-state platform with unprecedented controllability for studies of correlated quantum phenomena. To date, experimental studies have focused on the correlated electronic states; the…
In this work we are interested to studying the Kondo effect present in a system with a $T$-shape ligation between a single-wall carbon nanotube (SWNT) and a magnetic impurity. The system has been studied under hydrostatic pressure and it…
Effective low-energy Hamiltonian of interacting electrons in conducting single-wall carbon nanotubes with arbitrary chirality is derived from the microscopic lattice model. The parameters of the Hamiltonian show very weak dependence on the…
We theoretically study the interplay between electrical and mechanical properties of suspended, doubly clamped carbon nanotubes in which charging effects dominate. In this geometry, the capacitance between the nanotube and the gate(s)…
We report high field magneto-optical study on the first and second sub-band transitions of single-chirality single-walled carbon nanotubes. The ordering and relative energy splitting between bright and dark excitonic states were found to be…
Excitonic insulators are electronically-driven phases of matter characterized by the spontaneous condensation of electron-hole pairs. Here we show that La$_3$Cd$_2$As$_6$ undergoes a transition at $T_{0}=278$ K to a highly insulating state…
The interaction driven transition between quantum spin-Hall and Mott insulators in the Bernevig, Hughes and Zhang model is studied by dynamical cluster approximation, and found to be accompanied by the emergence of Green's function zeros…
Carbon nanotubes provide a remarkably versatile system in which to explore the effects of Coulomb interactions in one dimension. The most dramatic effects of strong electron-electron repulsion are *orthogonality catastrophes*. These…