Negative magnetoresistance due to conductivity fluctuations in films of the topological semimetal 
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Schumann, Timo; Goyal, Manik; Kealhofer, David; Stemmer, Susanne

doi:10.1103/physrevb.95.241113

Cited by 75 publications

(48 citation statements)

References 34 publications

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“…Moreover, the negative MR resulting from this effect should be hardly dependent on the angle between B and I. Third, conductivity fluctuation mechanism 47 can also lead to negative MR, which exists at very high temperatures, while we only observe the negative MR up to 70 K. Finally, our conclusion that the negative MR in SrAs 3 is induced by the chiral anomaly is consistent with the nontrivial π Berry phase. Our own calculations and those in ref.…”

Section: Discussionsupporting

confidence: 76%

Evidence for a Dirac nodal-line semimetal in SrAs3

Guo

et al. 2018

Science Bulletin

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Dirac nodal-line semimetals with the linear bands crossing along a line or loop, represent a new topological state of matter. Here, by carrying out magnetotransport measurements and performing first-principle calculations, we demonstrate that such a state has been realized in highquality single crystals of SrAs 3 . We obtain the nontrivial π Berry phase by analysing the Shubnikov-de Haas quantum oscillations. We also observe a robust negative longitudinal magnetoresistance induced by the chiral anomaly. Accompanying first-principles calculations identify that a single hole pocket enclosing the loop nodes is responsible for these observations.

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Section: Discussionsupporting

confidence: 76%

Evidence for a Dirac nodal-line semimetal in SrAs3

Guo

et al. 2018

Science Bulletin

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“…However, the temperature dependence of the NLMR in our quantum wells, as shown in Fig 1d. for Sample W1b, differs significantly from those reported in the literature, where NLMR diminishes monotonically with increasing temperature 9,10,21,22 . In contrast, the NLMR in our GaAs quantum wells shows a non-monotonic temperature behaviour and becomes most pronounced at ~170 K. This difference could be understood with the existence of two types of microscopic disorders in quantum wells.…”

Section: Resultscontrasting

confidence: 97%

“…The longitudinal magnetoconductance σ xx in thin films of topological insulator Bi 2 Se 3 21 is found to follow in magnetic fields up to 30 T, indicating that the entire sample is disordered. The behaviour of NLMRs in films of Dirac semimetal Cd 3 As 2 is thickness-dependent 22 , with various types of R ( B ) relationship resembling those in Supplementary Figure 7. In the scenario of Supplementary Figure 7c for a parallel equivalent circuit, Eq.…”

Section: Discussionmentioning

confidence: 69%

Negative longitudinal magnetoresistance in gallium arsenide quantum wells

Meng

Sultanov

et al. 2019

Nat Commun

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Negative longitudinal magnetoresistances (NLMRs) have been recently observed in a variety of topological materials and often considered to be associated with Weyl fermions that have a defined chirality. Here we report NLMRs in non-Weyl GaAs quantum wells. In the absence of a magnetic field the quantum wells show a transition from semiconducting-like to metallic behaviour with decreasing temperature. We observe pronounced NLMRs up to 9 Tesla at temperatures above the transition and weak NLMRs in low magnetic fields at temperatures close to the transition and below 5 K. The observed NLMRs show various types of magnetic field behaviour resembling those reported in topological materials. We attribute them to microscopic disorder and use a phenomenological three-resistor model to account for their various features. Our results showcase a contribution of microscopic disorder in the occurrence of unusual phenomena. They may stimulate further work on tuning electronic properties via disorder/defect nano-engineering.

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“…Cd 3 As 2 films were grown by MBE on relaxed, epitaxial (Ga 1-x In x )Sb buffer layers on (111)B GaAs substrates with a miscut of 3°towards 11 2 . The Cd 3 As 2 MBE parameters have been reported elsewhere [18,21]. The In content of the buffer layers (x), and thus their lattice parameter, was systematically varied.…”

Section: Experimental Methodsmentioning

confidence: 99%

Surface states of strained thin films of the Dirac semimetal Cd3As2

Goyal

Kim

Schumann

et al. 2019

Phys. Rev. Materials

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We report on the growth and transport properties of strained thin films of the three-dimensional Dirac semimetal Cd 3 As 2. Epitaxial heterostructures, consisting of (112)-oriented Cd 3 As 2 films, are grown on nearly lattice matched (Ga 1-x In x)Sb buffer layers on (111) GaAs substrates by molecular beam epitaxy. The epitaxial coherency strain breaks the fourfold rotational symmetry, which protects the bulk Dirac nodes in Cd 3 As 2. All strained films exhibit the quantum Hall effect with most carriers residing in the two-dimensional states, irrespective of the sign of the biaxial stress. The Hall mobility monotonically increases as the biaxial stress is changed from compressive towards tensile. Furthermore, pronounced anisotropy is seen in the transport properties. The results show that the quantum Hall effect, which is quite similar to that of unstrained (112)oriented films, is independent of the presence of bulk Dirac nodes. Its appearance is consistent with the topological surface states that are a characteristic of the topological Z 2 invariant.

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Negative magnetoresistance due to conductivity fluctuations in films of the topological semimetal Cd3As2

Cited by 75 publications

References 34 publications

Evidence for a Dirac nodal-line semimetal in SrAs3

Evidence for a Dirac nodal-line semimetal in SrAs3

Negative longitudinal magnetoresistance in gallium arsenide quantum wells

Surface states of strained thin films of the Dirac semimetal Cd3As2

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