Quantum Hall states observed in thin films of Dirac semimetal Cd3As2

Uchida, Masaki; Nakazawa, Yusuke; Nishihaya, Shinichi; Akiba, Kazuto; Kriener, Markus; Kozuka, Y.; Miyake, Atsushi; Taguchi, Y.; Tokunaga, Masashi; Nagaosa, Naoto; Tokura, Y.; Kawasaki, Masashi

doi:10.1038/s41467-017-02423-1

Cited by 153 publications

(151 citation statements)

References 44 publications

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“…As a result, cadmium arsenide now is among the most explored materials in current solid-state physics. In addition to the extraordinarily high electronic mobility, cadmium arsenide exhibits a very strong linear magneto-resistance [6], an anomalous Nernst effect [27], and quantum Hall effect signatures when thinned down [28,29]. Furthermore, indications of the chiral anomaly, planar Hall effect, and electron transport through surface states have been reported [30][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

3D Dirac semimetal Cd3As2 : A review of material properties

Crassee

Sankar

Lee

et al. 2018

Phys. Rev. Materials

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Cadmium arsenide (Cd3As2) -a time-honored and widely explored material in solid-state physics -has recently attracted considerable attention. This was triggered by a theoretical prediction concerning the presence of 3D symmetry-protected massless Dirac electrons, which could turn Cd3As2 into a 3D analogue of graphene. Subsequent extended experimental studies have provided us with compelling experimental evidence of conical bands in this system, and revealed a number of interesting properties and phenomena. At the same time, some of the material properties remain the subject of vast discussions despite recent intensive experimental and theoretical efforts, which may hinder the progress in understanding and applications of this appealing material. In this review, we focus on the basic material parameters and properties of Cd3As2, in particular those which are directly related to the conical features in the electronic band structure of this material. The outcome of experimental investigations, performed on Cd3As2 using various spectroscopic and transport techniques within the past sixty years, is compared with theoretical studies. These theoretical works gave us not only simplified effective models, but more recently, also the electronic band structure calculated numerically using ab initio methods.

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Section: Introductionmentioning

confidence: 99%

3D Dirac semimetal Cd3As2 : A review of material properties

Crassee

Sankar

Lee

et al. 2018

Phys. Rev. Materials

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“…It is important to note, that up to now, all indications of the SC phase emergence in Cd 3 As 2 were related either to the pressureinduced structural changes or to the proximity effect with the conventional s-wave SC [21,22].Recent studies of Cd 3 As 2 thin films outlined their specific features. The observation of quantum Hall state [23,24] and consecutive analysis of magnetoresistance of Cd 3 As 2 films suggest the existence of closed Fermi loops (Weyl orbits) related to the surface states, below some critical thickness [25,26]. Thus, superconducting Cd 3 As 2 thin film with nontrivial pairing (TSC state) should yield surface Majoranna modes, which, however, can be modified (in comparison to the bulk crystal [16]) due to interaction of opposite surfaces.In the previous studies bulk Cd 3 As 2 has not exhibited any indications of superconductivity except that arising at extremely high pressure.…”

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confidence: 99%

Observation of subkelvin superconductivity in Cd3As2 thin films

et al. 2019

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We report the first experimental observation of superconductivity in Cd3As2 thin films without application of external pressure. Surface studies suggest that the observed transport characteristics are related to the polycrystalline continuous part of investigated films with homogeneous distribution of elements and the Cd-to-As ratio close to stoichiometric Cd3As2. The latter is also supported by Raman spectra of the studied films, which are similar to those of Cd3As2 single crystals. The formation of superconducting phase in films under study is confirmed by the characteristic behavior of temperature and magnetic field dependence of samples resistances, as well as by the presence of pronounced zero-resistance plateaux in dV /dI characteristics. The corresponding Hc−Tc plots reveal a clearly pronounced linear behavior within the intermediate temperature range, similar to that observed for bulk Cd3As2 and Bi2Se3 films under pressure, suggesting the possibility of nontrivial pairing in the films under investigation. We discuss a possible role of sample inhomogeneities and crystal strains in the observed phenomena.Weyl and Dirac semimetals (WSM and DSM) currently attract wide interest related to the existence of Dirac nodes in their electron spectrum and related nontrivial topological characteristics of both bulk and surface states [1][2][3]. A special attention is drawn to the Cd 3 As 2 compound, which proved to be air-stable, unlike some other DSM materials [4][5][6][7][8]. This compound is known and has been studied for quite a long time [9][10][11][12]. Nevertheless, it is still very popular since the Dirac nodes of this semimetal are protected by the crystal symmetry and the electron states exhibit interesting topological properties, such as spin-momentum locking. Due to the high symmetry, DSM materials can undergo transitions to other topological phases (e.g. WSM) as a result of breaking certain symmetries or applying some external factors.The existence of topologically protected electron states gives a new impetus to the problem of topological superconductivity (TSC) being discussed for a long time [13][14][15]. In particular, Refs. [16,17] provide a theoretical analysis of the possible types of SC pairing in the systems of Cd 3 As 2 type, including topologically nontrivial ones. Basically, the existence of nontrivial pairing potential (leading to the emergence of triplet Cooper pairs) should induce the formation of Majoranna modes at the surface of the crystal, which can be used in the faulttolerant quantum computing [14]. The SC phase emergence in Cd 3 As 2 was reported in Ref.[18], however, it was observed at pressures above the structural transition from the tetragonal to trigonal phase. While theoretical works suggest the stabilization of TSC phase upon such symmetry lowering [16,17], such transition also implies appearance of the gap at Dirac nodes, thus, suppressing the DSM phase. Additional indications of the SC phase in Cd 3 As 2 were also observed in the point-contact spectroscopy experiments and att...

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“…Low carrier densities [4,35,36] and gating [36] have also been achieved. The 3D quantum Hall effect of the Fermi arcs is expected in slabs of the TaAs family [37-39, 42-46, 210, 214], [110] or [110] Cd 3 As 2 [35,[216][217][218][219], and [100] or [010] Na 3 Bi. In the presence of a residual detuning from the Weyl nodes, the bulk states also contribute to σ s H .…”

Section: A Wormhole Tunneling Via Fermi Arcs and Weyl Nodesmentioning

confidence: 99%

Quantum transport in topological semimetals under magnetic fields (II)

Sun

2019

Front. Phys.

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We review our recent works on the quantum transport, mainly in topological semimetals and also in topological insulators, organized according to the strength of the magnetic field. At weak magnetic fields, we explain the negative magnetoresistance in topological semimetals and topological insulators by using the semiclassical equations of motion with the nontrivial Berry curvature. We show that the negative magnetoresistance can exist without the chiral anomaly. At strong magnetic fields, we establish theories for the quantum oscillations in topological Weyl, Dirac, and nodal-line semimetals. We propose a new mechanism of 3D quantum Hall effect, via the "wormhole" tunneling through the Weyl orbit formed by the Fermi arcs and Weyl nodes in topological semimetals. In the quantum limit at extremely strong magnetic fields, we find that an unexpected Hall resistance reversal can be understood in terms of the Weyl fermion annihilation. Additionally, in parallel magnetic fields, longitudinal resistance dips in the quantum limit can serve as signatures for topological insulators.

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Quantum Hall states observed in thin films of Dirac semimetal Cd3As2

Cited by 153 publications

References 44 publications

3D Dirac semimetal Cd3As2 : A review of material properties

3D Dirac semimetal Cd3As2 : A review of material properties

Observation of subkelvin superconductivity in Cd3As2 thin films

Quantum transport in topological semimetals under magnetic fields (II)

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