Related papers: A Charge-Density-Wave Topological Semimetal
We study the electronic structure of bulk 1T-TaSe$_2$ in the charge density wave phase at low temperature. Our spatially and angle resolved photoemission (ARPES) data show insulating areas coexisting with metallic regions characterized by a…
Monolayer transition metal dichalcogenides in the distorted octahedral 1T$^\prime$ phase exhibit a large bulk bandgap and gapless boundary states, which is an asset in the ongoing quest for topological electronics. In single-layer tungsten…
In this work, we study the out-of-equilibrium dynamics of the paradigmatic quasi-one-dimensional material (TaSe$_4$)$_2$I, that exhibits a transition into an incommensurate CDW phase when cooled just below room temperature, namely at…
TaTe$_4$ is a quasi-1D tetrachalcogenide that exhibits a CDW instability caused by a periodic lattice distortion. Recently, pressure-induced superconductivity has been achieved in this compound, revealing a competition between these…
Topological insulators and topological semimetals are both new classes of quantum materials, which are characterized by surface states induced by the topology of the bulk band structure. Topological Dirac or Weyl semimetals show linear…
Coherent phonon excitation offers a nonthermal route to control quantum phases of condensed matter. In this work, we employ first-principles calculations to investigate the phonon landscape of (TaSe4)2I in its charge-density-wave (CDW)…
Charge density wave (CDW) is a collective quantum phenomenon with a charge modulation in solids1-2. Condensation of electron and hole pairs with finite momentum will lead to such an ordered state3-7. However, lattice symmetry breaking…
Following our results that the two-body interaction can induce a space and time dependent topological axion term $ \frac{e^2}{2\pi \hbar}\theta(z,t)(\vec{E}\cdot\vec{B})$, we show that by applying this theory to a Weyl semimetal with two…
A search for new topological quantum systems is challenging due to the requirement of non{trivial band connectivity that leads to protected surface states of electrons. A progress in this field was primarily due to a realization of band…
A charge density wave (CDW) of a nonzero ordering vector $\mathbf{q}$ couple electronic states at $\mathbf{k}$ and $\mathbf{k}+\mathbf{q}$ statically, giving rise to a reduced Brillouin zone (RBZ) due to the band folding effect. Its…
Following the intense studies on topological insulators, significant efforts have recently been devoted to the search for gapless topological systems. These materials not only broaden the topological classification of matter but also…
We study for the first time the effects of strong short-range electron-electron interactions in generic Rarita--Schwinger--Weyl semimetals hosting spin-3/2 electrons with linear dispersion at a four-fold band crossing point. The emergence…
The presence of electron correlations in a system with topological order can lead to exotic ground states. Considering single crystals of LaAgSb2 which has a square net crystal structure, one finds multiple charge density wave transitions…
Three-dimensional (3D) topological Weyl semimetals (TWSs) represent a novel state of quantum matter with unusual electronic structures that resemble both a "3D graphene" and a topological insulator by possessing pairs of Weyl points…
How strong correlations and topology interplay is a topic of great current interest. In this perspective paper, we focus on correlation-driven gapless phases. We take the time-reversal symmetric Weyl semimetal as an example because it is…
We present a study of "nodal semimetal" phases, in which non-degenerate conduction and valence bands touch at points (the "Weyl semimetal") or lines (the "line node semimetal") in three-dimensional momentum space. We discuss a general…
Shortly after the discovery of Weyl semimetals properties related to the topology of their bulk band structure have been observed, e.g. signatures of the chiral anomaly and Fermi arc surface states. These essentially single particle…
Layered transition metal chalcogenides are promising hosts of electronic Weyl nodes and topological superconductivity. MoTe$_2$ is a striking example that harbors both noncentrosymmetric T$_d$ and centrosymmetric T' phases, both of which…
The charge density wave (CDW) in 1T-TiSe2 accompanied by the periodic lattice distortion has a nontrivial symmetry configuration. The symmetry is important as an indication of the mechanism and a cue for experimental probes. We examine the…
We review recent experimental progresses on layered topological materials, mainly focusing on transitional metal dichalcogenides with various lattice types including 1T, Td and 1T' structural phases. Their electronic quantum states are…