scholarly journals Magnetism-induced topological transition in EuAs3

2020 ◽  
Author(s):  
Erjian Cheng ◽  
Wei Xia ◽  
Jie Xu ◽  
Chengwei Wang ◽  
Chuanying Xi ◽  
...  
Keyword(s):  
Electrical Transport ◽  
Berry Phase ◽  
Magnetic Moments ◽  
Surface States ◽  
Nodal Line ◽  
Chiral Anomaly ◽  
Topological Transition ◽  
Spin Polarized ◽  
Exotic Physics ◽  
Topological Semimetals

Abstract The nature of the interaction between magnetism and topology in magnetic topological semimetals remains mysterious, but may be expected to lead to a variety of novel physics. We present ab initio band calculations, electrical transport and angle-resolved photoemission spectroscopy (ARPES) measurements on the magnetic semimetal EuAs3, demonstrating a magnetism-induced topological transition from a topological nodal-line semimetal in the paramagnetic or the spin-polarized state to a topological massive Dirac metal in the antiferromagnetic (AFM) ground state at low temperature, featuring a pair of massive Dirac points, inverted bands and topological surface states on the (010) surface. Shubnikov-de Haas (SdH) oscillations in the AFM state identify nonzero Berry phase and a negative longitudinal magnetoresistance (n-LMR) induced by the chiral anomaly, confirming the topological nature predicted by band calculations. When magnetic moments are fully polarized by an external magnetic field, an unsaturated and extremely large magnetoresistance (XMR) of ∼ 2×105 % at 1.8 K and 28.3 T is observed, likely arising from topological protection. Consistent with band calculations for the spin-polarized state, four new bands in quantum oscillations different from those in the AFM state are discerned, of which two are topologically protected. Nodal-line structures at the Y point in the Brillouin zone (BZ) are proposed in both the spin-polarized and paramagnetic states, and the latter is proven by ARPES. Moreover, a temperature-induced Lifshitz transition accompanied by the emergence of a new band below 3 K is revealed. These results indicate that magnetic EuAs3 provides a rich platform to explore exotic physics arising from the interaction of magnetism with topology.

scholarly journals Magnetism-induced topological transition in EuAs3

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Erjian Cheng ◽  
Wei Xia ◽  
Xianbiao Shi ◽  
Hongwei Fang ◽  
Chengwei Wang ◽  
...  
Keyword(s):  
Electrical Transport ◽  
Nodal Line ◽  
Photoemission Spectroscopy ◽  
Topological Transition ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Spin Polarized ◽  
Lifshitz Transition ◽  
Antiferromagnetic Ground State ◽  
Exotic Physics ◽  
Topological Semimetals

AbstractThe nature of the interaction between magnetism and topology in magnetic topological semimetals remains mysterious, but may be expected to lead to a variety of novel physics. We systematically studied the magnetic semimetal EuAs3, demonstrating a magnetism-induced topological transition from a topological nodal-line semimetal in the paramagnetic or the spin-polarized state to a topological massive Dirac metal in the antiferromagnetic ground state at low temperature. The topological nature in the antiferromagnetic state and the spin-polarized state has been verified by electrical transport measurements. An unsaturated and extremely large magnetoresistance of ~2 × 105% at 1.8 K and 28.3 T is observed. In the paramagnetic states, the topological nodal-line structure at the Y point is proven by angle-resolved photoemission spectroscopy. Moreover, a temperature-induced Lifshitz transition accompanied by the emergence of a new band below 3 K is revealed. These results indicate that magnetic EuAs3 provides a rich platform to explore exotic physics arising from the interaction of magnetism with topology.

Chiral anomaly and nontrivial Berry phase in the topological nodal-line semimetal SrAs3

2019 ◽  
Vol 99 (4) ◽  
Author(s):  
Linlin An ◽  
Xiangde Zhu ◽  
Wenshuai Gao ◽  
Min Wu ◽  
Wei Ning ◽  
...  
Keyword(s):  
Berry Phase ◽  
Nodal Line ◽  
Chiral Anomaly

scholarly journals Transport of Topological Semimetals

2019 ◽  
Vol 49 (1) ◽  
pp. 207-252 ◽  
Author(s):  
Jin Hu ◽  
Su-Yang Xu ◽  
Ni Ni ◽  
Zhiqiang Mao
Keyword(s):  
Transport Properties ◽  
Structural Characteristics ◽  
Nodal Point ◽  
Experimental Studies ◽  
Anomalous Hall Effect ◽  
Nodal Line ◽  
Chiral Anomaly ◽  
Energy Excitation ◽  
Topological Semimetal ◽  
Topological Semimetals

Three-dimensional (3D) topological semimetals represent a new class of topological matters. The study of this family of materials has been at the frontiers of condensed matter physics, and many breakthroughs have been made. Several topological semimetal phases, including Dirac semimetals (DSMs), Weyl semimetals (WSMs), nodal-line semimetals (NLSMs), and triple-point semimetals, have been theoretically predicted and experimentally demonstrated. The low-energy excitation around the Dirac/Weyl nodal points, nodal line, or triply degenerated nodal point can be viewed as emergent relativistic fermions. Experimental studies have shown that relativistic fermions can result in a rich variety of exotic transport properties, e.g., extremely large magnetoresistance, the chiral anomaly, and the intrinsic anomalous Hall effect. In this review, we first briefly introduce band structural characteristics of each topological semimetal phase, then review the current studies on quantum oscillations and exotic transport properties of various topological semimetals, and finally provide a perspective of this area.

scholarly journals The study of magnetic topological semimetals by first principles calculations

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Jinyu Zou ◽  
Zhuoran He ◽  
Gang Xu
Keyword(s):  
Surface States ◽  
Nodal Line ◽  
Future Research ◽  
Honeycomb Lattice ◽  
Space Groups ◽  
Type Iv ◽  
Fermi Arcs ◽  
Topological Quantum ◽  
Recent Developments ◽  
Topological Semimetals

Abstract Magnetic topological semimetals (TSMs) are topological quantum materials with broken time-reversal symmetry (TRS) and isolated nodal points or lines near the Fermi level. Their topological properties would typically reveal from the bulk-edge correspondence principle as nontrivial surface states such as Fermi arcs or drumhead states, etc. Depending on the degeneracies and distribution of the nodes in the crystal momentum space, TSMs are usually classified into Weyl semimetals (WSMs), Dirac semimetals (DSMs), nodal-line semimetals (NLSMs), triple-point semimetals (TPSMs), etc. In this review article, we present the recent advances of magnetic TSMs from a computational perspective. We first review the early predicted magnetic WSMs such as pyrochlore iridates and HgCr2Se4, as well as the recently proposed Heusler, Kagome layers, and honeycomb lattice WSMs. Then we discuss the recent developments of magnetic DSMs, especially CuMnAs in Type-III and EuCd2As2 in Type-IV magnetic space groups (MSGs). Then we introduce some magnetic NLSMs that are robust against spin–orbit coupling (SOC), namely Fe3GeTe2 and LaCl (LaBr). Finally, we discuss the prospects of magnetic TSMs and the interesting directions for future research.

Electrical transport properties of cerium doped Bi2Te3 thin films grown by molecular beam epitaxy

2021 ◽  
Vol 42 (12) ◽  
pp. 122902
Author(s):  
Peng Teng ◽  
Tong Zhou ◽  
Yonghuan Wang ◽  
Ke Zhao ◽  
Xiegang Zhu ◽  
...  
Keyword(s):  
Thin Films ◽  
Molecular Beam Epitaxy ◽  
Electrical Transport ◽  
Kondo Effect ◽  
Molecular Beam ◽  
Magnetic Moments ◽  
Surface States ◽  
Electrical Transport Properties ◽  
Doping Effects ◽  
Topological Surface

Abstract Introducing magnetism into topological insulators (TIs) can tune the topological surface states and produce exotic physical effects. Rare earth elements are considered as important dopant candidates, due to their large magnetic moments from heavily shielded 4f electrons. As the first element with just one 4f electron, cerium (Ce) offers an ideal platform for exploring the doping effect of f-electron in TIs. Here in this work, we have grown cerium-doped topological insulator Bi2Te3 thin films on an Al2O3(0001) substrate by molecular beam epitaxy (MBE). Electronic transport measurements revealed the Kondo effect, weak anti-localization (WAL) effect and suppression of surface conducting channels by Ce doping. Our research shows the fundamental doping effects of Ce in Bi2Te3 thin films, and demonstrates that such a system could be a good platform for further research.

scholarly journals Glide symmetry protected higher-order topological insulators from semimetals with butterfly-like nodal lines

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Xiaoting Zhou ◽  
Chuang-Han Hsu ◽  
Cheng-Yi Huang ◽  
Mikel Iraola ◽  
Juan L. Mañes ◽  
...  
Keyword(s):  
Topological Insulator ◽  
Topological Insulators ◽  
Surface States ◽  
Nodal Line ◽  
Higher Order ◽  
Dirac Fermion ◽  
Space Groups ◽  
Nodal Lines ◽  
Topological Semimetals ◽  
Symmetry Protected

AbstractMost topological insulators (TIs) discovered today in spinful systems can be transformed from topological semimetals (TSMs) with vanishing bulk gap via introducing the spin-orbit coupling (SOC), which manifests the intrinsic links between the gapped topological insulator phases and the gapless TSMs. Recently, we have discovered a family of TSMs in time-reversal invariant spinless systems, which host butterfly-like nodal-lines (NLs) consisting of a pair of identical concentric intersecting coplanar ellipses (CICE). In this Communication, we unveil the intrinsic link between this exotic class of nodal-line semimetals (NLSMs) and a $${{\mathbb{Z}}}_{4}$$ Z 4 = 2 topological crystalline insulator (TCI), by including substantial SOC. We demonstrate that in three space groups (i.e., Pbam (No.55), P4/mbm (No.127), and P42/mbc (No.135)), the TCI supports a fourfold Dirac fermion on the (001) surface protected by two glide symmetries, which originates from the intertwined drumhead surface states of the CICE NLs. The higher order topology is further demonstrated by the emergence of one-dimensional helical hinge states, indicating the discovery of a higher order topological insulator protected by a glide symmetry.

scholarly journals Anomalous Hall effect in Weyl semimetal half-Heusler compounds RPtBi (R = Gd and Nd)

2018 ◽  
Vol 115 (37) ◽  
pp. 9140-9144 ◽  
Author(s):  
Chandra Shekhar ◽  
Nitesh Kumar ◽  
V. Grinenko ◽  
Sanjay Singh ◽  
R. Sarkar ◽  
...  
Keyword(s):  
Hall Effect ◽  
Muon Spin ◽  
Surface States ◽  
Anomalous Hall Effect ◽  
Chiral Anomaly ◽  
Heusler Compounds ◽  
Weyl Semimetal ◽  
Spin Resonance ◽  
Topological Surface ◽  
Topological Semimetals

Topological materials ranging from topological insulators to Weyl and Dirac semimetals form one of the most exciting current fields in condensed-matter research. Many half-Heusler compounds, RPtBi (R = rare earth), have been theoretically predicted to be topological semimetals. Among various topological attributes envisaged in RPtBi, topological surface states, chiral anomaly, and planar Hall effect have been observed experimentally. Here, we report an unusual intrinsic anomalous Hall effect (AHE) in the antiferromagnetic Heusler Weyl semimetal compounds GdPtBi and NdPtBi that is observed over a wide temperature range. In particular, GdPtBi exhibits an anomalous Hall conductivity of up to 60 Ω−1⋅cm−1 and an anomalous Hall angle as large as 23%. Muon spin-resonance (μSR) studies of GdPtBi indicate a sharp antiferromagnetic transition (TN) at 9 K without any noticeable magnetic correlations above TN. Our studies indicate that Weyl points in these half-Heuslers are induced by a magnetic field via exchange splitting of the electronic bands at or near the Fermi energy, which is the source of the chiral anomaly and the AHE.

scholarly journals Topological semimetal in honeycomb lattice LnSI

2017 ◽  
Vol 114 (40) ◽  
pp. 10596-10600 ◽  
Author(s):  
Simin Nie ◽  
Gang Xu ◽  
Fritz B. Prinz ◽  
Shou-cheng Zhang
Keyword(s):  
Condensed Matter ◽  
Surface States ◽  
Nodal Line ◽  
Honeycomb Lattice ◽  
Nodal Lines ◽  
Weyl Semimetal ◽  
The Standard Model ◽  
Weyl Semimetals ◽  
Topological Semimetals ◽  
The Right

Recognized as elementary particles in the standard model, Weyl fermions in condensed matter have received growing attention. However, most of the previously reported Weyl semimetals exhibit rather complicated electronic structures that, in turn, may have raised questions regarding the underlying physics. Here, we report promising topological phases that can be realized in specific honeycomb lattices, including ideal Weyl semimetal structures, 3D strong topological insulators, and nodal-line semimetal configurations. In particular, we highlight a semimetal featuring both Weyl nodes and nodal lines. Guided by this model, we showed that GdSI, the long-perceived ideal Weyl semimetal, has two pairs of Weyl nodes residing at the Fermi level and that LuSI (YSI) is a 3D strong topological insulator with the right-handed helical surface states. Our work provides a mechanism to study topological semimetals and proposes a platform for exploring the physics of Weyl semimetals as well as related device designs.

scholarly journals Double-bowl state in photonic Dirac nodal line semimetal

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Mengying Hu ◽  
Ye Zhang ◽  
Xi Jiang ◽  
Tong Qiao ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Surface States ◽  
Nodal Line ◽  
Electronic Systems ◽  
Nodal Lines ◽  
Spectrum Range ◽  
The Past ◽  
Topological Materials ◽  
Classical Waves ◽  
Topological Semimetals ◽  
Polarized Surface

AbstractThe past decade has seen a proliferation of topological materials for both insulators and semimetals in electronic systems and classical waves. Topological semimetals exhibit topologically protected band degeneracies, such as nodal points and nodal lines. Dirac nodal line semimetals (DNLS), which own four-fold line degeneracy, have drawn particular attention. DNLSs have been studied in electronic systems but there is no photonic DNLS. Here in this work, we provide a new mechanism, which is unique for photonic systems to investigate a stringent photonic DNLS. When truncated, the photonic DNLS exhibits double-bowl states (DBS), which comprise two sets of perpendicularly polarized surface states. In sharp contrast to nondegenerate surface states in other photonic systems, here the two sets of surface states are almost degenerate over the whole-spectrum range. The DBS and the bulk Dirac nodal ring (DNR) dispersion along the relevant directions, are experimentally resolved.

scholarly journals Electrical transport properties and Kondo effect in La1−xPrxNiO3−δ thin films

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Van Hien-Hoang ◽  
Nak-Kwan Chung ◽  
Heon-Jung Kim
Keyword(s):  
Thin Films ◽  
Electrical Transport ◽  
Kondo Effect ◽  
Magnetic Moments ◽  
Structural Disorder ◽  
Strongly Correlated ◽  
Electrical Transport Properties ◽  
Strongly Correlated Electron ◽  
Correlated Electron Systems ◽  
Correlated Electron

AbstractThe Kondo effect has been a topic of intense study because of its significant contribution to the development of theories and understanding of strongly correlated electron systems. In this work, we show that the Kondo effect is at work in La1−xPrxNiO3−δ (0 ≤ x ≤ 0.6) thin films. At low temperatures, the local magnetic moments of the 3d eg electrons in Ni2+, which form because of oxygen vacancies, interact strongly with itinerant electrons, giving rise to an upturn in resistivity with x ≥ 0.2. Observation of negative magnetoresistance, described by the Khosla and Fisher model, further supports the Kondo picture. This case represents a rare example of the Kondo effect, where Ni2+ acts as an impurity in the background of Ni3+. We suggest that when Ni2+ does not participate in the regular lattice, it provides the local magnetic moments needed to scatter the conduction electrons in the Kondo effect. These results offer insights into emergent transport behaviors in metallic nickelates with mixed Ni3+ and Ni2+ ions, as well as structural disorder.

Sign in / Sign up

Export Citation Format

Share Document