Optical signatures of Dirac nodal lines in NbAs
            <sub>2</sub>

Shao, Yinming; Sun, Zhiyuan; Wang, Ying; Xu, Chenchao; Sankar, Raman; Breindel, Alexander; Cao, Chao; Fogler, M. M.; Millis, Andrew J.; Chou, F. C.; Li, Zhiqiang; Timusk, T.; Maple, M. B.; Basov, D. N.

doi:10.1073/pnas.1809631115

Cited by 66 publications

(55 citation statements)

References 59 publications

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“…For example, pressure‐induced superconductivity is obtained at 2.63 K and 12.8 GPa in the topological semimetal NbAs 2 without a structural transition . A linear Dirac dispersion was recently detected in NbAs 2 through magneto‐optical measurements . A negative magnetoresistance is widely observed in NbAs 2 , as predicted .…”

Section: Pressure‐induced Superconductivitysupporting

confidence: 58%

“…High‐pressure conditions make performing crucial experiments, such as ARPES, to test the nontrivial topological properties difficult, and pressure‐induced structural transitions make such experiments even more complicated. Consequently, investigating the topological semimetals that become superconducting without a structural transition under pressure, such as WTe 2 , MoP, and NbAs 2 , is relatively more meaningful. For example, pressure‐induced superconductivity is obtained at 2.63 K and 12.8 GPa in the topological semimetal NbAs 2 without a structural transition .…”

Section: Pressure‐induced Superconductivitymentioning

confidence: 99%

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Exploring Topological Superconductivity in Topological Materials

2019

Adv Quantum Tech

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The exploration of topological superconductivity and Majorana zero modes has become a rapidly developing field. Many types of proposals to realize topological superconductors have been presented, and significant advances have been recently made. In this review, a survey is conducted on the experimental progress in possible topological superconductors and induced superconductivity in topological insulators or semimetals as well as artificial structures. The approaches to inducing superconductivity in topological materials mainly include high pressure application, the hard-tip point contact method, chemical doping or intercalation, the use of artificial topological superconductors, and electric field gating. The evidence supporting topological superconductivity and signatures of Majorana zero modes are also discussed and summarized.

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Section: Pressure‐induced Superconductivitysupporting

confidence: 58%

Section: Pressure‐induced Superconductivitymentioning

confidence: 99%

Exploring Topological Superconductivity in Topological Materials

2019

Adv Quantum Tech

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“…In contrast, AHC is only sensitive to the one crossing Fermi level [7,[13][14][15][16][17]. Second, on considering optical selection rule and peak position, one can definitely identify the contributions from Weyl nodes [18][19][20]. Third, transport measurements like AHC requires high techniques and high quality of the whole device [15? ].…”

mentioning

confidence: 99%

“…At 5 K, both the steep plasma edge in reflectivity ( Fig. S1 in supplementary material [21]) and the ultra-narrow Drude peak in optical conductivity reflect the coherence of the linear bands [18,19].…”

mentioning

confidence: 99%

Magnetization-Induced Band Shift in Ferromagnetic Weyl Semimetal Co3Sn2S2
Yang
¹
,
Zhang
²
,
Zhou
³

et al. 2020
Phys. Rev. Lett.
53
4
36
0
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The discovery of nonmagnetic Weyl semimetals (WSMs) in TaAs compounds has triggered lots of efforts in finding its magnetic counterpart. While the direct observation of the Weyl nodes and Fermi arcs in a magnetic candidate through angle-resolved photoemission spectroscopy is hindered by the complex magnetic domains. The transport features of magnetic WSMs, including negative magnetoresistivity and anomalous Hall conductivity, are not conclusive since these are sensitive to extrinsic factors like defects and disorders in lattice or magnetic ordering. Here, we systematically study the temperature dependent optical spectra of ferromagnetic Co3Sn2S2 experimentally and simulated by first-principles calculations. The many-body correlation effect due to Co 3d electrons leads to renormalization of bands by a factor about 1.33, which is moderate and the description within density functional theory is suitable. As temperature drops down, the magnetic phase transition happens and the magnetization drives the band shift through exchange splitting. The optical spectra can well detect these changes, including the transitions sensitive and insensitive to the magnetization, and those from the bands around the Weyl nodes. The results strongly support that Co3Sn2S2 is a magnetic WSM and the Weyl nodes can be tuned by magnetization with temperature change.PACS numbers: 72.15.-v, 74.70.-b, 78.30.-j Recently, the shandite compound Co 3 Sn 2 S 2 has attracted lots of attentions since it not only shows intrinsic ferromagnetism but also is proposed to have three pairs of Weyl points around the Fermi level in the first Brillouin zone (BZ) [1-3, 5]. For its quasi-two-dimensional crystal structure, low carrier density and strong anomalous Hall effect (AHE), Co 3 Sn 2 S 2 has been thought as a potential candidate to realize the quantum AHE [6,7] in its tow-dimensional (2D) limit [1,8,9]. As a candidate of magnetic Weyl semimetal (WSM) [10], the magnetic ordering states are expected to have interactions with Weyl nodes [2,3], so that the topological properties from WSM can be finely tuned through control of magnetization [2,11]. Actually, it has been found that upon cooling, the magnetization and anomalous Hall conductivity (AHC) of Co 3 Sn 2 S 2 vary accordingly [1, 2] and the first-principles calculations of AHC at different magnetization has shown their intrinsic relationship through the changes in the position of Weyl nodes [2]. To check whether this picture is true or not in realistic samples, here we have performed systematical optical spectra measurements under different temperatures (T s). The advantages of optical spectra measurements over the AHC measurements are as following: First, optical spectrum is * These authors contributed equally to this work. † hmweng@iphy.ac.cn ‡ xgqiu@iphy.ac.cn

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“…One can compare their method to dowsing, the folklore practice of searching for underground water, minerals, or anything invisible indirectly by observing the motion of a pointer or the changes in direction of a pendulum (https://en.wikipedia.org/wiki/Dowsing). In the case of Shao et al (1), their method actually works and is interpreted using a theory of the scaling relations. As a bonus, the authors suggest that the nascent nodal lines might explain an unusually strong magnetoresistance of the family of related dipnictides, XPn 2 , where X = {Ta, Nb} and Pn = {P, As, Sb} (4-6).…”

mentioning

confidence: 99%