Plasmon mode as a detection of the chiral anomaly in Weyl semimetals

Zhou, Jinhong; Chang, Hao-Ran

doi:10.1103/physrevb.91.035114

Cited by 149 publications

(183 citation statements)

References 43 publications

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“…Moreover, the dispersion reveals a subtle logarithmic electron charge renormalization effect which is an additional specific signature of a three-dimensional Dirac system. Note that previous work exclusively studies the plasmon mode at zero temperature [11][12][13][14][15]. In this Rapid Communication, we establish a different mechanism for finite-temperature plasmons which arises due to the thermal excitation of electrons from the valence to the conduction band.…”

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confidence: 64%

Plasmon signature in Dirac-Weyl liquids

Hofmann

Sarma

2015

Phys. Rev. B

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We consider theoretically as a function of temperature the plasmon mode arising in threedimensional Dirac liquids, i.e., systems with linear chiral relativistic single-particle dispersion, within the random phase approximation. We find that whereas no plasmon mode exists in the intrinsic (undoped) system at zero temperature, there is a well-defined finite-temperature plasmon with superlinear temperature dependence, rendering the plasmon dispersion widely tunable with temperature. The plasmon dispersion contains a logarithmic correction due to the ultraviolet-logarithmic renormalization of the electron charge, manifesting a fundamental many-body interaction effect as in quantum electrodynamics. The plasmon dispersion of the extrinsic (doped) system displays a minimum at finite temperature before it crosses over to the superlinear intrinsic behavior at higher temperature, implying that the high-temperature plasmon is a universal feature of Dirac liquids irrespective of doping. This striking characteristic temperature dependence of intrinsic Dirac plasmons along with the logarithmic renormalization is a unique manifestation of the three-dimensional relativistic Dirac nature of quasiparticle excitations and serves as an experimentally observable signature of three-dimensional Dirac materials. In Dirac semimetals the valence and conduction bands touch only in isolated points of the Brillouin zone with a Fermi energy that is tuned close to these band touching points, giving rise to particle excitations with an effective linear relativistic band dispersion ε ± (k) = ± v F k. Much of the interest in these novel materials stems from the topological properties of Weyl semimetals which are manifest in anomalous transport properties [1,2] and Fermi arc surface states [3]. Recent hallmark experiments have realized these materials in Cd 3 As 2 , Na 3 Bi, and TaAs and have demonstrated the Dirac cone structure in ARPES measurements [4][5][6][7][8][9] and detected topological surface states in Na 3 Bi and TaAs [9,10]. These initial experiments, which serve to verify the expected band structure, motivate the search for definitive experimental signatures of Dirac materials which establish unique observable effects distinct from standard electron gases and normal metals. In this Rapid Communication, we show that the collective charge oscillation of a Dirac liquid, the plasmon, is widely tunable as a superlinear function of temperature (with ∼ −T / ln T ), which allows us to extract high-precision information on the Dirac material. Moreover, the dispersion reveals a subtle logarithmic electron charge renormalization effect which is an additional specific signature of a three-dimensional Dirac system. Note that previous work exclusively studies the plasmon mode at zero temperature [11][12][13][14][15]. In this Rapid Communication, we establish a different mechanism for finite-temperature plasmons which arises due to the thermal excitation of electrons from the valence to the conduction band. It turns out that this interband mechanis...

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confidence: 64%

Plasmon signature in Dirac-Weyl liquids

Hofmann

Sarma

2015

Phys. Rev. B

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“…This has been attracting a lot of theoretical efforts, such as the prediction of negative parallel magnetoresistance [24][25][26][27], proposal of non-local transport [28], using electronic circuits [29], plasmon mode [30], etc. In particular, whether or not the chiral anomaly could produce measurable magnetoconductivity is one of the focuses in recent efforts.…”

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confidence: 99%

High-field magnetoconductivity of topological semimetals with short-range potential

2015

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Weyl semimetals are three-dimensional topological states of matter, in a sense that they host paired monopoles and antimonopoles of Berry curvature in momentum space, leading to the chiral anomaly. The chiral anomaly has long been believed to give a positive magnetoconductivity or negative magnetoresistivity in strong and parallel fields. However, several recent experiments on both Weyl and Dirac topological semimetals show a negative magnetoconductivity in high fields. Here, we study the magnetoconductivity of Weyl and Dirac semimetals in the presence of shortrange scattering potentials. In a strong magnetic field applied along the direction that connects two Weyl nodes, we find that the conductivity along the field direction is determined by the Fermi velocity, instead of by the Landau degeneracy. We identify three scenarios in which the high-field magnetoconductivity is negative. Our findings show that the high-field positive magnetoconductivity may not be a compelling signature of the chiral anomaly and will be helpful for interpreting the inconsistency in the recent experiments and earlier theories.

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“…The nodal point semimetals include Dirac semimetals(DSM) [4][5][6][7][8][9][10][11][12][13][14] and Weyl semimetals(WSM) [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. The main feature of the band structures of DSMs and WSMs is the linear bandtouching points ("Dirac points" and "Weyl points"), which are responsible for most of their interesting properties, including novel phenomena induced by the chiral anomaly [32][33][34][35][36][37][38][39][40][41][42][43][44]. NLSMs [45][46][47][48][49][50][51][52]…”

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confidence: 99%

Tunable Weyl Points in Periodically Driven Nodal Line Semimetals

2016

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Weyl semimetals and nodal line semimetals are characterized by linear band touching at zero-dimensional points and one-dimensional lines, respectively. We predict that a circularly polarized light drives nodal line semimetals into Weyl semimetals. The Floquet Weyl points thus obtained are tunable by the incident light, which enables investigations of them in a highly controllable manner. The transition from nodal line semimetals to Weyl semimetals is accompanied by the emergence of a large and tunable anomalous Hall conductivity. Our predictions are experimentally testable by transport measurement in film samples or by pump-probe angleresolved photoemission spectroscopy. 71.70.Ej,75.70.Tj It has become well known that topological concepts underlie many fascinating phenomena in condensed matter physics. After in-depth investigations of topological insulators [1][2][3], considerable attention is now focused on topological semimetals. Unlike topological insulators, whose gapless excitations always live at the sample boundary, topological semimetals host gapless fermions in the bulk. The two major classes of topological semimetals under intense study are (i) nodal point semimetals and (ii) nodal line semimetals (NLSM). The nodal point semimetals include Dirac semimetals(DSM) [4][5][6][7][8][9][10][11][12][13][14] and Weyl semimetals(WSM) [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. The main feature of the band structures of DSMs and WSMs is the linear bandtouching points ("Dirac points" and "Weyl points"), which are responsible for most of their interesting properties, including novel phenomena induced by the chiral anomaly [32][33][34][35][36][37][38][39][40][41][42][43][44]. NLSMs [45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63] differ in that they contain band-touching lines or rings [107], away from which the dispersion is linear.In this Letter we show that driving NLSMs by a circularly polarized light (CPL) creates WSMs, namely, nodal lines become nodal points under radiations. Our work was motivated by recent progress in Floquet topological states [64][65][66][67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83], in particular, Ref. [84] showed that incident light can shift the locations of Weyl points in WSMs. The effect we predict in NLSMs is more dramatic: band-touching lines are driven to points; thus, the dimension of the band-touching manifold is changed. Meanwhile, a large anomalous Hall conductivity tunable by the incident light emerges. Unlike the photoinduced Hall effect in WSMs [84], which is proportional to intensity of incident light, the Hall conductivity in our systems is large and quite insensitive to the light intensity at low temperature, though it depends sensitively on the incident angle of light. The surface Fermi arcs of the Floquet WSMs have a simple interpretation, namely, it comes from tilting the drumhead surface dispersion of NLSMs.The Floquet WSMs derived from NLSMs are highly tunable, in particular, the Weyl poi...

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Plasmon mode as a detection of the chiral anomaly in Weyl semimetals

Cited by 149 publications

References 43 publications

Plasmon signature in Dirac-Weyl liquids

Plasmon signature in Dirac-Weyl liquids

High-field magnetoconductivity of topological semimetals with short-range potential

Tunable Weyl Points in Periodically Driven Nodal Line Semimetals

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