相关论文: Electronic Properties Close to Dirac Cone in Two-D…
We show a zero-gap semiconducting (ZGS) state in the quasi-two-dimensional organic conductor $\alpha$-(BEDT-TTF)$_2$I$_3$ salt, which emerges under uniaxial pressure along the a-axis (the stacking axis of the BEDT-TTF molecule). The ZGS…
The electric conductivity which reveals the zero gap semiconducting (ZGS) state has been investigated as the function of temperature $T$ and life time $\tau$ in order to understand the ZGS state in quarter-filled…
In neutral graphene dots the Fermi level coincides with the Dirac points. We have investigated in the presence of a magnetic field several unusual properties of single electron states near the Fermi level of such a rectangular-shaped…
Dirac electrons with a zero-gap state (ZGS) in organic conductor $\alpha$-(BEDT-TTF)$_2$I$_3$ result from a fine tuning of the seven nearest neighbors transfer integrals ($a_1, a_2, a_3, b_1, b_2, b_3, b_4$) between the four molecules of…
Mani et al. have observed [1] zero-resistance states (ZRS) and energy gaps in a surprising setting: ultrahigh-mobility GaAs/AlGaAs heterostructures that contain a two dimensional electron Landau system (2DELS) exhibit vanishing diagonal…
We investigate the formation of density waves in the zero-gap state (ZGS) which has been found in the quasi-two-dimensional organic conductor $\alpha$-(BEDT-TTF)$_2$I$_3$ salt under the hydrostatic pressure. The ZGS exhibits the cone-like…
Superconductivity and ferromagnetism are generally competing ground states in $d$-electron systems, making their interplay of fundamental interest. We report a comprehensive study of high-quality single- and polycrystalline V$_2$Ga$_5$, a…
We have discovered two-dimensional zero-gap material with a layered structure in the organic conductor $\alpha$-(BEDT-TTF)$_2$I$_3$ under high hydrostatic pressure. In contrast to graphene, the electron-hole symmetry is not good except at…
(BEDT-TFF)$_2$I$_3$ charge transfer salts are reported to show superconductivity and pressure induced quasi two-dimensional Dirac cones at the Fermi level. By performing state of the art ab initio calculations in the framework of density…
The nature of the insulating ground state in quasi-two-dimensional organic conductor lambda-(BETS)_2GaX_zY_{4-z}, where the existence of a spin gap is suggested by susceptibility measurement, has been studied theoretically. Hartree-Fock…
The quasi-two-dimensional molecular semimetallic conductor $\alpha$-STF$_2$I$_3$ is isostructural with $\alpha$-ET$_2$I$_3$.The latter possesses a unique band structure showing a zero-gap state with Dirac cones under high pressure, whereas…
The effects of electron correlation in the quasi-two-dimensional organic conductor \alpha-(BEDT-TTF)2I3 are investigated theoretically by using an extended Hubbard model with on-site and nearest-neighbor Coulomb interactions. A variational…
The conducting state of the quasi-two-dimensional organic conductor, $\alpha$-(BEDT-TTF)$_2$I$_3$, at ambient pressure is investigated with $^{13}$C NMR measurements, which separate the local electronic states at three nonequivalent…
The electric conductivity of Dirac electrons in the organic conductor $\alpha$-STF$_2$I$_3$ (STF = bis(ethylenedithio)diselenadithiafulvalene), which has an isostructure of ET(=bis(ethylenedithio)tetrathiafulvalene), has been theoretically…
We review the role of strong electronic correlations in quasi--two-dimensional organic charge transfer salts such as (BEDT-TTF)$_2X$, (BETS)$_2Y$ and $\beta'$-[Pd(dmit)$_2$]$_2Z$. We begin by defining minimal models for these materials. It…
The energies as a function of the magnetic field ($H$) and the pressure are studied theoretically in the tight-binding model for the two-dimensional organic conductor, $\alpha$-(BEDT-TTF)$_2$I$_3$, in which massless Dirac fermions are…
We employed first-principles density-functional theory (DFT) calculations to characterize Dirac electrons in quasi-two-dimensional molecular conductor $\alpha$-(BETS)$_2$I$_3$ [= $\alpha$-(BEDT-TSeF)$_2$I$_3$] at a low temperature of 30K.…
Dirac- and Weyl point- and line-node semimetals are characterized by a zero band gap with simultaneously vanishing density of states. Given a sufficient interaction strength, such materials can undergo an interaction instability, e.g., into…
Graphene, renowned for its exceptional electronic and optical properties as a robust 2D material, traditionally lacks electronic correlation effects. Proximity coupling offers a promising method to endow quantum materials with novel…
We study the electronic and transport properties of a graphene-based superlattice theoretically by using an effective Dirac equation. The superlattice consists of a periodic potential applied on a single-layer graphene deposited on a…