High-resolution angle-resolved photoemission study of LaSb

Kumigashira, Hiroshi; Kim, Hyeong–Do; Ito, Takahiro; Ashihara, A.; Takahashi, Takashi; Suzuki, Takeru; Nishimura, M.; Sakai, Osamu; Kaneta, Yasunori; Harima, Hisatomo

doi:10.1103/physrevb.58.7675

Cited by 49 publications

(27 citation statements)

References 17 publications

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“…In Fig. 3(b), there is a clear anticrossing of the β and ε bands along theΓ -X direction, which is predicted by band structure calculations 22 but was not observed in the previous ARPES data 28,39,48 . Interestingly, there are two apparent Dirac points at theX point -DP2 and DP3 occur at binding energies of −0.16 and −0.35 eV, respectively.…”

Section: Resultsmentioning

confidence: 56%

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Presence of exotic electronic surface states in LaBi and LaSb

et al. 2016

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Extremely high magnetoresistance (XMR) in the lanthanum monopnictides LaX (X = Sb, Bi) has recently attracted interest in these compounds as candidate topological materials. However, their perfect electron-hole compensation provides an alternative explanation, so the possible role of topological surface states requires verification through direct observation. Our angle-resolved photoemission spectroscopy (ARPES) data reveal multiple Dirac-like surface states near the Fermi level in both materials. Intriguingly, we have observed circular dichroism in both surface and near-surface bulk bands. Thus the spin-orbit coupling-induced orbital and spin angular momentum textures may provide a mechanism to forbid backscattering in zero field, suggesting that surface and near-surface bulk bands may contribute strongly to XMR in LaX. The extremely simple rock salt structure of these materials and the ease with which high-quality crystals can be prepared suggests that they may be an ideal platform for further investigation of topological matter.

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Section: Resultsmentioning

confidence: 56%

“…3(d), demonstrating the close similarity to LaBi. An additional hole-like band ζ is observed which can be found in the bulk band calculations 48 .…”

Section: Resultsmentioning

confidence: 69%

Presence of exotic electronic surface states in LaBi and LaSb

et al. 2016

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“…Further examining the measured FSs carefully, we can observe additional FSs around X perpendicular to the elongated pocket along the Γ-X direction, which is a common feature in the LnX series of compounds; this could be possibly interpreted by the band folding effect as a consequence of breaking translational symmetry from bulk to the (001) surface 53 . Moreover, the k z broadening effect caused by the short escape length of the photoelectrons excited by the vacuum ultraviolet light in our ARPES experiments may also be an alternative explanation 49,[56][57][58] .…”

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confidence: 85%

Evidence of topological insulator state in the semimetal LaBi

Lou

Bao

et al. 2017

Phys. Rev. B

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By employing angle-resolved photoemission spectroscopy combined with first-principles calculations, we performed a systematic investigation on the electronic structure of LaBi, which exhibits extremely large magnetoresistance (XMR), and is theoretically predicted to possess band anticrossing with nontrivial topological properties. Here, the observations of the Fermi-surface topology and band dispersions are similar to previous studies on LaSb [Phys. Rev. Lett. 117, 127204 (2016)], a topologically trivial XMR semimetal, except the existence of a band inversion along the Γ-X direction, with one massless and one gapped Dirac-like surface state at the X and Γ points, respectively. The odd number of massless Dirac cones suggests that LaBi is analogous to the time-reversal Z 2 nontrivial topological insulator. These findings open up a new series for exploring novel topological states and investigating their evolution from the perspective of topological phase transition within the family of rare-earth monopnictides.PACS numbers: 73.20. At, 71.18.+y, 71.20.Eh Exploring exotic topological states has sparked extensive research interest, both theoretically and experimentally, due to their promising potential in low consumption spintronics devices 1-3 . In the past decade, since the discovery of quantum spin Hall effect in graphene 4 , remarkable achievements have been reached, including the findings of twodimensional (2D) 5-7 and three-dimensional (3D) topological insulators (TIs) 8 , node-line semimetals 9,10 , topological crystalline insulators 11,12 , and Dirac and Weyl semimetals [13][14][15][16][17][18] . Strikingly, although the TIs have ignited the whole field for years, the realization of novel massless surface Dirac fermions, i.e., topological surface states (SSs), is still pretty exciting due to the great prospects in tunability of the topological characteristics through easily accessible manipulations 19 . Among the extensive efforts, the study on the topological phase transition (TPT) can also effectively facilitate the exploration and investigation of topological SSs and even the Dirac semimetals [20][21][22] .Recently, the discovery of simple rock salt rare-earth monopnictides LnX (Ln = La, Y, Nd, or Ce; X = Sb/Bi) [23][24][25][26][27][28][29] has renewed the platform for searching these novel topological states. The most remarkable signature of this series is the extremely large magnetoresistance (XMR) with a resistivity plateau at low temperatures, which is proposed as the consequence of breaking time-reversal symmetry 23 . However, the theoretical predictions for the topological properties vary in the LnX series 30 . In addition, similar fingerprints have also been reported in several semimetals including TmPn 2 (Tm = Ta/Nb, Pn = As/Sb) 31-36 , ZrSiS 37-39 , WTe 2 40 , Cd 3 As 2 41,42 , TaAs 43 , and NbP 44 . The topological origin of the large magnetoresistance and resistivity plateau is still under debate. Furthermore, the rich and interesting topological phases predicted in the LnX family offer an ...

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“…This has been also confirmed by the experimental fact that overall band structure of CeSb is almost the same as that of LaSb, which has no 4 f electrons. 30 On the other hand, in USb, the bare 5 f level is positioned well above the Sb 5p band and very close to E F , so that the p-f mixing no longer gives any energy gain for the magnetic transition. The close proximity of the U 5 f level to E F causes the energy instability and consequently leads to the significant valence fluctuation with the U 6d conduction band.…”

Section: Near-e F Regionmentioning

confidence: 98%

High-resolution angle-resolved photoemission study of USb: Dual character of5felectrons

et al. 2000

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We have performed a high-resolution angle-resolved photoemission spectroscopy ͑ARPES͒ on antiferromagnetic USb to study the electronic structure near the Fermi level. We found that USb has a metallic band structure with the fully occupied Sb 5p bands in contrast to semimetallic CeSb that has the partially filled Sb 5p bands. This suggests that the magnetic phase transition of USb is not understood within the framework of the p-f mixing model. This difference in the electronic structure between USb and CeSb is ascribed to the energy position of the respective bare f level with respect to the Sb 5p band. The observed fully occupied Sb 5p bands in USb is consistent with the band calculation based on the itinerant U 5 f model, but different from that of the localized model. On the other hand, we found two dispersionless bands just below E F in ARPES spectra of USb, which are well described in terms of the 5 f 2 -final-state multiplet structure calculated based on the localized 5 f model. These experimental results suggest the dual ͑itinerant and localized͒ character of 5 f electrons that characterizes anomalous properties of USb.

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High-resolution angle-resolved photoemission study of LaSb

Cited by 49 publications

References 17 publications

Presence of exotic electronic surface states in LaBi and LaSb

Presence of exotic electronic surface states in LaBi and LaSb

Evidence of topological insulator state in the semimetal LaBi

High-resolution angle-resolved photoemission study of USb: Dual character of5felectrons

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