Similar ultrafast dynamics of several dissimilar Dirac and Weyl semimetals

Weber, Carsten; Berggren, Bryan; Masten, Madison G.; Ogloza, Thomas; Deckoff-Jones, Skylar; Madéo, Julien; Man, Michael K. L.; Dani, Keshav M.; Zhao, Lingxiao; Chen, Genfu; Liu, Jinyu; Mao, Zhiqiang; Schoop, Leslie M.; Lotsch, Bettina V.; Parkin, Stuart S. P.; Ali, Mazhar N.

doi:10.1063/1.5006934

Cited by 45 publications

(41 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Rapid photo relaxation has been seen in all kinds of different types of Dirac semimetals. 228 The future for applications of TSMs in optical devices thus seems bright.…”

Section: Optical Propertiesmentioning

confidence: 99%

Chemical Principles of Topological Semimetals

2018

Self Cite

View full text Add to dashboard Cite

PrefaceThe recent rapid development in the field of topological materials raises expectations that these materials might allow solving a large variety of current challenges in condensed matter science, ranging from applications in quantum computing, to infra-red sensors or heterogenous catalysis. 1-8 In addition, exciting predictions of completely new physical phenomena that could arise in topological materials drive the interest in these compounds. 9,10 For example, charge carriers might behave completely different from what we expect from the current laws of physics if they travel through topologically non-trivial systems. 11,12 This happens because charge carriers in topological materials can be different from the normal type of fermions we know, which in turn affects the transport properties of the material. It has also been proposed that we could even find "new fermions", i.e. fermions that are different from the types we currently know in condensed matter systems as well as in particle physics. 10 Such proposals connect the fields of high energy or particle physics, whose goal it is to understand the universe and all the particles it is composed of, with condensed matter physics, 1 arXiv:1804.10649v1 [cond-mat.mtrl-sci] 27 Apr 2018where the same type, or even additional types, of particles can be found as so-called quasiparticles, meaning that the charge carriers behave in a similar way as it would be expected from a certain particle existing in free space.The field of topology in condensed matter physics evolved from the idea that there can be insulators whose band structure is fundamentally different (i.e. has a different topology) from that of the common insulators we know. If two insulators with different topologies are brought into contact, electrons that have no mass and cannot be back scattered are supposed to appear at the interface. These edge states also appear if a topological insulator (TI) is in contact with air, a trivial insulator. 2D TIs have conducting edge states whereas 3D TIs, which were discovered later, have conducting surface states. TIs have already been reviewed multiple times, [13][14][15][16] which is why we focus here on the newer kind of topological materials, namely topological semimetals (TSMs). Nevertheless, we will refer to TIs and their properties where relevant in the context of topological materials and to contrast them with TSMs.The term "topological semimetal" is widely used and basically includes all semimetals that exhibit some non-trivial band topology. We will describe in more detail later in this review what non-trivial topology actually means. Since TSMs are semimetals they are characterized by a gap-less band structure, i.e. they differ from normal metals by being charge balanced, meaning the amount of electrons and holes contributing to their conductivity is exactly the same. Or, phrased differently, the hole and electron pockets composing the Fermi surface are of the same size.

show abstract

“…Rapid photo relaxation has been seen in all kinds of different types of Dirac semimetals. 228 The future for applications of TSMs in optical devices thus seems bright.…”

Section: Optical Propertiesmentioning

confidence: 99%

Chemical Principles of Topological Semimetals

2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…Several Shubnikov-de-Haas (SdH) oscillations measurements reported a major peak at ∼240 T, which is attributed to the quasi-2D Fermi surface [16,19,[21][22][23][24][25] while a peak at ∼600 T observed by thermoelectric power [23] and high field SdH [24] measurement is assigned to a 3D Fermi surface. Recently, frequency independent flat optical conductivity [25], the rapid relaxation rate after photoexcitation [26] and Ag tip induced superconductivity [27] are also reported in ZrSiS. Thus, these fascinating phenomena demonstrated that the ZrSiS family is a great system for studying the Dirac nodal-lines [11,12,28,29].…”

Section: Introductionmentioning

confidence: 97%

Surface termination dependent quasiparticle scattering interference and magneto-transport study on ZrSiS

Wang

et al. 2018

New J. Phys.

View full text Add to dashboard Cite

Dirac nodal line semimetals represent a new state of quantum matters in which the electronic bands touch to form a closed loop with linear dispersion. Here, we report a combined study on ZrSiS by density functional theory calculation, scanning tunnelling microscope (STM) and magneto-transport measurements. Our STM measurements reveal the spectroscopic signatures of a diamond-shaped Dirac bulk band and a surface band on two types of cleaved surfaces as well as a spin-polarized surface band at G at E∼0.6 eV on S-surface, consistent with our band calculation. Furthermore, we find the surface termination does not affect the surface spectral weight from the Dirac bulk bands but greatly affect the surface bands due to the change in the surface orbital composition. From our magnetotransport measurements, the primary Shubnikov-de-Haas frequency is identified to stem from the hole-type quasi-two-dimensional Fermi surface between Γ and X. The extracted non-orbital magnetoresistance (MR) contribution D(θ, H) yields a nearly H-linear dependence, which is attributed to the intrinsic MR in ZrSiS. Our results demonstrate the unique Dirac line nodes phase and the dominating role of Zr-d orbital on the electronic structure in ZrSiS and the related compounds.

show abstract

“…For the magnetic behavior, it displays ferromagnetic (FM) order below T C ∼ 565 K, followed by a transition to canted antiferromagnetic (AFM) order with a net FM component below T F M −AF M ≈ 304 K [3]. The nontrivial topological semimetal behavior was further supported by optical conductivity and ultrafast optical pump-probe measurements [4]. Nevertheless, Ramankutty et al[5] reported zero Berry phase indicative of trivial topology in nearly stoichiometric SrMnSb 2 .…”

mentioning

confidence: 99%

“…4 (f)-(h), these Dirac cones form a line node along the Y-S direction, and two Dirac cones merge at the S point. This is a consequence of two units of MnSb(2) 4 and Sb(1) layers, each of which supports two-dimensional Dirac cones, and the mixing between the two units is suppressed at k x = π.…”

mentioning

confidence: 99%

Influence of magnetism on Dirac semimetallic behavior in nonstoichiometric Sr1−yMn1−zSb2(y
Zhang
¹
,
Okamoto
²
,
Stone
³

et al. 2019
Phys. Rev. B
Self Cite
13
5
17
0
View full text Add to dashboard Cite

Nonstoichiometric Sr1−yMn1−zSb2 (y, z <0.1) is known to exhibit a coexistence of magnetic order and the nontrivial semimetallic behavior related to Dirac or Weyl fermions. Here, we report inelastic neutron scattering analyses of the spin dynamics and density functional theory studies on the electronic properties of Sr1−yMn1−zSb2. We observe a relatively large spin excitation gap ≈ 8.5 meV at 5 K, and the interlayer magnetic exchange constant only 2.8 % of the dominant intralayer magnetic interaction, providing evidence that Sr1−yMn1−zSb2 exhibits a quasi-2D magnetism. Using density functional theory, we find a strong influence of magnetic orders on the electronic band structure and the Dirac dispersions near the Fermi level along the Y-S direction in the presence of a ferromagnetic ordering. Our study unveils novel interplay between the magnetic order, magnetic transition, and electronic property in Sr1−yMn1−zSb2, and opens new pathways to control the relativistic band structure through magnetism in ternary compounds.Topological semimetals [1, 2] are a newly emerged frontier in condensed matter physics and have stimulated tremendous research interest because they give access to new quantum phenomena and are very attractive for both fundamental research and technological application. Particular attention has focused on Weyl or Dirac semimetals that exibit a coexistence with magnetism as a promising route to modify and control Weyl/Dirac fermions, electronic transport properties and band topology, among which SrMnSb 2 has attracted much interest recently. Liu et al.[3] reported a nontrivial semimetallic behavior related to Dirac or Weyl fermions including nearly massless quasiparticles with a π Berry phase coupled to ferromagnetism in nonstoichiometric Sr 1−y Mn 1−z Sb 2 . For the magnetic behavior, it displays ferromagnetic (FM) order below T C ∼ 565 K, followed by a transition to canted antiferromagnetic (AFM) order with a net FM component below T F M −AF M ≈ 304 K [3]. The nontrivial topological semimetal behavior was further supported by optical conductivity and ultrafast optical pump-probe measurements [4]. Nevertheless, Ramankutty et al.[5] reported zero Berry phase indicative of trivial topology in nearly stoichiometric SrMnSb 2 . Previous density functional theory (DFT) calculations [5][6][7] showed that the lattice distortion in the orthorhombic structure prevents the formation of the Dirac points near the Fermi level by opening a gap. Both results cannot account for the observed topological semimetallic behavior reported in Ref.[3]. It is therefore challenging to explore whether there are indeed Dirac/Weyl points in proximity to the Fermi level and what drives their formation in Sr 1−y Mn 1−z Sb 2 . Furthermore, SrMnSb 2 offers a wonderful opportunity to address an important question whether there is a close correlation between magnetic order and band topology in 3D Dirac compounds.In addition to SrMnSb 2 , other Alkaline earth ternary AMnC 2 "112" compounds (A =Sr, Ca, Ba, C= Bi or Sb) [8][9][10][11][12]...

show abstract

Similar ultrafast dynamics of several dissimilar Dirac and Weyl semimetals

Cited by 45 publications

References 62 publications

Chemical Principles of Topological Semimetals

Chemical Principles of Topological Semimetals

Surface termination dependent quasiparticle scattering interference and magneto-transport study on ZrSiS

Influence of magnetism on Dirac semimetallic behavior in nonstoichiometric Sr1−yMn1−zSb2(y
Zhang
¹
,
Okamoto
²
,
Stone
³

et al. 2019
Phys. Rev. B
Self Cite
13
5
17
0
View full text Add to dashboard Cite

Contact Info

Product

Resources

About

Similar ultrafast dynamics of several dissimilar Dirac and Weyl semimetals

Cited by 45 publications

References 62 publications

Chemical Principles of Topological Semimetals

Chemical Principles of Topological Semimetals

Surface termination dependent quasiparticle scattering interference and magneto-transport study on ZrSiS

Influence of magnetism on Dirac semimetallic behavior in nonstoichiometric Sr1−yMn1−zSb2(yZhang1, Okamoto2, Stone3 et al. 2019Phys. Rev. BSelf Cite135170View full textAdd to dashboardCite

Contact Info

Product

Resources

About

Influence of magnetism on Dirac semimetallic behavior in nonstoichiometric Sr1−yMn1−zSb2(y
Zhang
¹
,
Okamoto
²
,
Stone
³

et al. 2019
Phys. Rev. B
Self Cite
13
5
17
0
View full text Add to dashboard Cite