نتایج جستجو برای: Dirac semimetal

تعداد نتایج: 20016  

2015
Cai-Zhen Li Li-Xian Wang Haiwen Liu Jian Wang Zhi-Min Liao Da-Peng Yu

Dirac electronic materials beyond graphene and topological insulators have recently attracted considerable attention. Cd3As2 is a Dirac semimetal with linear dispersion along all three momentum directions and can be viewed as a three-dimensional analogue of graphene. By breaking of either time-reversal symmetry or spatial inversion symmetry, the Dirac semimetal is believed to transform into a W...

2017
Hannes Hübener Michael A Sentef Umberto De Giovannini Alexander F Kemper Angel Rubio

Tuning and stabilizing topological states, such as Weyl semimetals, Dirac semimetals or topological insulators, is emerging as one of the major topics in materials science. Periodic driving of many-body systems offers a platform to design Floquet states of matter with tunable electronic properties on ultrafast timescales. Here we show by first principles calculations how femtosecond laser pulse...

Journal: :Physical review letters 2014
Koji Kobayashi Tomi Ohtsuki Ken-Ichiro Imura Igor F Herbut

The quantum phase transition between the three dimensional Dirac semimetal and the diffusive metal can be induced by increasing disorder. Taking the system of a disordered Z2 topological insulator as an important example, we compute the single particle density of states by the kernel polynomial method. We focus on three regions: the Dirac semimetal at the phase boundary between two topologicall...

Journal: :Nanoscale 2015
Marc Dvorak Zhigang Wu

The honeycomb lattice of graphene is characterized by linear dispersion and pseudospin chirality of fermions on the Dirac cones. If lattice anisotropy is introduced, the Dirac cones stay intact but move in reciprocal space. Dirac point movement can lead to a topological transition from semimetal to semiconductor when two inequivalent Dirac points merge, an idea that has attracted significant re...

Journal: :Physical review letters 2017
Han-Jin Noh Jinwon Jeong En-Jin Cho Kyoo Kim B I Min Byeong-Gyu Park

A Dirac fermion in a topological Dirac semimetal is a quadruple-degenerate quasiparticle state with a relativistic linear dispersion. Breaking either time-reversal or inversion symmetry turns this system into a Weyl semimetal that hosts double-degenerate Weyl fermion states with opposite chiralities. These two kinds of quasiparticles, although described by a relativistic Dirac equation, do not ...

2017
Huaqing Huang Feng Liu

The extremely stringent requirement on material quality has hindered the investigation and potential applications of exotic chiral magnetic effect in Dirac semimetals. Here, we propose that gray tin is a perfect candidate for observing the chiral anomaly effect and Shubnikov-de-Haas (SdH) oscillation at relatively low magnetic field. Based on effective k·p analysis and first-principles calculat...

Journal: :Physical review letters 2015
J H Pixley Pallab Goswami S Das Sarma

We study the quantum phase diagram of a three dimensional noninteracting Dirac semimetal in the presence of either quenched axial or scalar potential disorder, by calculating the average and the typical density of states as well as the inverse participation ratio using numerically exact methods. We show that as a function of the disorder strength a half-filled (i.e., undoped) Dirac semimetal di...

2017
Alexandra V Galeeva Ivan V Krylov Konstantin A Drozdov Anatoly F Knjazev Alexey V Kochura Alexander P Kuzmenko Vasily S Zakhvalinskii Sergey N Danilov Ludmila I Ryabova Dmitry R Khokhlov

We demonstrate that measurements of the photo-electromagnetic effect using terahertz laser radiation provide an argument for the existence of highly conductive surface electron states with a spin texture in Dirac semimetals (Cd1-x Zn x )3As2. We performed a study on a range of (Cd1-x Zn x )3As2 mixed crystals undergoing a transition from the Dirac semimetal phase with an inverse electron energy...

Journal: :Physical review letters 2016
Benjamin J Wieder Youngkuk Kim A M Rappe C L Kane

We study a class of Dirac semimetals that feature an eightfold-degenerate double Dirac point. We show that 7 of the 230 space groups can host such Dirac points and argue that they all generically display linear dispersion. We introduce an explicit tight-binding model for space groups 130 and 135. Space group 135 can host an intrinsic double Dirac semimetal with no additional states at the Fermi...

2018
Huaqing Huang Kyung-Hwan Jin Feng Liu

Dirac, triple-point, andWeyl fermions represent three topological semimetal phases, characterized with a descending degree of band degeneracy, which have been realized separately in specific crystalline materials with different lattice symmetries. Here we demonstrate an alloy engineering approach to realize all three types of fermions in one single material system of MgTa2−xNbxN3. Based on symm...

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