Discovery of a Three-Dimensional Topological Dirac Semimetal, Na3Bi

  title={Discovery of a Three-Dimensional Topological Dirac Semimetal, Na3Bi},
  author={Z K Liu and B In Zhou and Y Zhang and Z. J. Wang and Hongming Weng and Dharmalingam Prabhakaran and S. K. Mo and Z. X. Shen and Zhong Fang and Xi Dai and Zahid Hussain and Y. L. Chen},
  pages={864 - 867}
A 3D Graphene? Discoveries of materials with exciting electronic properties have propelled condensed matter physics over the past decade. Two of the best-known examples, graphene and topological insulators, have something in common: a linear energy-momentum relationship—the Dirac dispersion—in their two-dimensional (2D) electronic states. Topological insulators also have a more mundane aspect of their electronic structure, characterized by a band gap. Another class of materials, topological… 
A stable three-dimensional topological Dirac semimetal Cd3As2.
By performing angle-resolved photoemission spectroscopy, a pair of 3D Dirac fermions in Cd3As2 are directly observed, proving that it is a model 3D TDS and by in situ doping it is able to tune its Fermi energy, making it a flexible platform for exploring exotic physical phenomena.
Electric control of topological phase transitions in Dirac semimetal thin films
This report investigates the possibility to induce and control the topological quantum spin Hall phase in a Dirac semimetal thin film by using a vertical electric field and shows that through the interplay between the quantum confinement effect and the field-induced coupling between sub-bands, the sub-band gap can be tuned and inverted.
Dimensional Crossover and Topological Phase Transition in Dirac Semimetal Na3Bi Films.
It is demonstrated that Dirac gaps emerge in Na3Bi films, providing spectroscopic evidences of dimensional crossover from a 3D semimetal to a 2D topological insulator.
Graphene analogues in bulk : the prediction and observation of 3 D Dirac semimetals
A large part of the enthusiasm for graphene studies stems from that material’s unusual electronic structure. Undoped graphene is a two-dimensional “Dirac” semimetal, meaning that at low energies and
Observation of a three-dimensional topological Dirac semimetal phase in high-mobility Cd3As2.
The discovery of the Dirac-like bulk topological semimetal phase in Cd3As2 opens the door for exploring higher dimensional spin-orbit Dirac physics in a real material.
Evidence of Topological Surface State in Three-Dimensional Dirac Semimetal Cd3As2
The electronic structure of Cd3As2 is investigated by angle-resolved photoemission measurements on the crystal surface and detailed band structure calculations and the topological surface state with a linear dispersion approaching the Fermi level is identified for the first time.
Observation of quasi-two-dimensional Dirac fermions in ZrTe5
Since the discovery of graphene, layered materials have attracted extensive interests owing to their unique electronic and optical characteristics. Among them, Dirac semimetal, one of the most
Planar Hall effect in the type-II Dirac semimetal VAl3
The study of electronic properties in topological systems is one of the most fascinating topics in condensed matter physics, which has generated enormous interests in recent times. New materials are
Elemental Topological Dirac Semimetal: α-Sn on InSb(111).
Using angle-resolved photoemission spectroscopy, 3D Dirac cones associated with bulk electronic states near the Fermi level are observed in epitaxially grown α-Sn films on InSb(111), the first such TDS system realized in an elemental form.
Observation of Fermi arc surface states in a topological metal
The systematic results collectively identify a topological phase in a gapless material and observe a pair of spin-polarized Fermi arc surface states on the surface of the Dirac semimetal Na3Bi at its native chemical potential.


Studies on the electronic structures of three-dimensional topological insulators by angle resolved photoemission spectroscopy
Three-dimensional (3D) topological insulators represent a new state of quantum matter with a bulk gap and odd number of relativistic Dirac fermions on the surface. The unusual surface states of
Topological semimetal and Fermi-arc surface states in the electronic structure of pyrochlore iridates
We investigate novel phases that emerge from the interplay of electron correlations and strong spin-orbit interactions. We focus on describing the topological semimetal, a three-dimensional phase of
Dirac semimetal and topological phase transitions in A 3 Bi ( A = Na , K, Rb)
Three-dimensional (3D) Dirac point, where two Weyl points overlap in momentum space, is usually unstable and hard to realize. Here we show, based on the first-principles calculations and effective
Colloquium : Topological insulators
Topological insulators are electronic materials that have a bulk band gap like an ordinary insulator but have protected conducting states on their edge or surface. These states are possible due to
Dirac semimetal in three dimensions.
It is shown that the pseudorelativistic physics of graphene near the Fermi level can be extended to three dimensional materials and β-cristobalite BiO(2) is metastable, so it can be physically realized as a 3D analog to graphene.
Weyl semimetal in a topological insulator multilayer.
The Weyl semimetal has a nonzero dc conductivity at zero temperature, but Drude weight vanishing as T(2), and is thus an unusual metallic phase, characterized by a finite anomalous Hall conductivity and topologically protected edge states.
Chern semimetal and the quantized anomalous Hall effect in HgCr2Se4.
It is predicted, based on first principles calculations, that such a novel quantum state can be realized in a known ferromagnetic compound HgCr2Se4, with a single pair of Weyl fermions separated in momentum space.
Topological insulators and superconductors
Topological insulators are new states of quantum matter which cannot be adiabatically connected to conventional insulators and semiconductors. They are characterized by a full insulating gap in the
Magnetic impurities on the surface of a topological insulator.
It is shown that a magnetic impurity opens up a local gap and suppresses the local density of states, and the case of quenched disorder through a renormalization group analysis is studied.
Topological aspect and quantum magnetoresistance of β-Ag2Te.
It is shown, by first principles calculations, that β-Ag2Te with distorted antifluorite structure is in fact a topological insulator with gapless Dirac-type surface states.