Related papers: $\beta$-As$_2$Te$_3$: Pressure-Induced 3D Dirac Se…
Two pressure-induced phase transitions have been theoretically studied in the layered iron phosphorus triselenide (FePSe3). Topological analysis of chemical bonding in FePSe3 has been performed based on the results of first-principles…
As an intermediate state in the topological phase diagram, Dirac semimetals are of particular interest as a platform for studying topological phase transitions under external modulations. Despite a growing theoretical interest in this…
Optical measurements and band structure calculations are reported on 3D Dirac materials. The electronic properties associated with the Dirac cone are identified in the reflectivity spectra of Cd$_3$As$_2$ and Na$_3$Bi single crystals. In…
Since the three dimensional (3D) Dirac semi-metal Cd$_3$As$_2$ exists close to topological phase boundaries, in principle it should be possible to drive it into exotic new phases, like topological superconductors, by breaking certain…
The three dimensional (3D) topological insulators are predicted to exhibit a 3D Dirac semimetal state in critical regime of topological to trivial phase transition. Here we demonstrate the first experimental evidence of 3D Dirac semimetal…
3D Dirac semi-metals (DSMs) are materials that have massless Dirac electrons and exhibit exotic physical properties It has been suggested that structurally distorting a DSM can create a Topological Insulator (TI), but this has not yet been…
High pressure electrical resistance and x-ray diffraction measurements have been performed on ruthenium-doped Ba(Fe0.9Ru0.1)2As2, up to pressures of 32 GPa and down to temperatures of 10 K, using designer diamond anvils under…
High pressure X-ray diffraction measurements have been carried out on the intermetallic semiconductor FeGa$_3$ and the equation of state for FeGa$_3$ has been determined. First principles based DFT calculations within the GGA approximation…
Three-dimensional topological insulators are characterized by the presence of a bandgap in their bulk and gapless Dirac fermions at their surfaces. New physical phenomena originating from the presence of the Dirac fermions are predicted to…
In a semimetal, both electron and hole carriers contribute to the density of states at the Fermi level. The small band overlaps and multi-band effects give rise to many novel electronic properties, such as relativistic Dirac fermions with…
Inducing a magnetic gap at the Dirac point of the topological surface state (TSS) in a 3D topological insulator (TI) is a route to dissipationless charge and spin currents. Ideally, magnetic order is present only at the surface and not in…
The electrical conductivity of suspended graphene has recently been measured for the first time, and found to behave as \sigma ~ \sqrt{|n|} as expected for Dirac quasiparticles at large carrier density. The charge inhomogeneity is strongly…
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…
Cadmium arsenide Cd$_3$As$_2$ hosts massless Dirac electrons in its ambient-conditions tetragonal phase. We report X-ray diffraction and electrical resistivity measurements of Cd$_3$As$_2$ upon cycling pressure beyond the critical pressure…
We measured the optical reflectivity of [001]-oriented $n$-doped Cd$_{3}$As$_{2}$ in a broad frequency range (50 - 22000 cm$^{-1}$) for temperatures from 10 to 300 K. The optical conductivity, $\sigma(\omega) = \sigma_{1}(\omega) + {\rm…
We report the structural, vibrational and electrical transport properties up to 16 GPa of the 1T-TiTe2, a prominent layered 2D system, which is predicted to show a series of topologically trivial - nontrivial transitions under hydrostatic…
Optical control of Dirac surface states (SS) in topological insulators (TI) remains one of the most challenging problems governing their potential applications in novel electronic and spintronic devices. Here, using visible-range transient…
We report the temperature-pressure phase diagram of CaKFe$_4$As$_4$ established using high pressure electrical resistivity, magnetization and high energy x-ray diffraction measurements up to 6 GPa. With increasing pressure, both resistivity…
In a Dirac semimetal, the conduction and valence bands contact only at discrete (Dirac) points in the Brillouin zone (BZ) and disperse linearly in all directions around these critical points. Including spin, the low energy effective theory…
We have investigated the band structure at the $\Gamma$ point of the three-dimensional (3D) topological insulator Bi$_2$Se$_3$ using magneto-spectroscopy over a wide range of energies ($0.55-2.2$\,eV) and in ultrahigh magnetic fields up to…