Anomalous quantum oscillations and evidence for a non-trivial Berry phase in SmSb

Abstract

Topologically non-trivial electronic structures can give rise to a range of unusual physical phenomena, and the interplay of band topology with other effects such as electronic correlations and magnetism requires further exploration. The rare earth monopnictides X(Sb,Bi) (X = lanthanide) are a large family of semimetals where these different effects may be tuned by the substitution of rare-earth elements. Here we observe anomalous behavior in the quantum oscillations of one member of this family, antiferromagnetic SmSb. The analysis of Shubnikov-de Haas (SdH) oscillations provides evidence for a non-zero Berry phase, indicating a non-trivial topology of the α-band. Furthermore, striking differences are found between the temperature dependence of the amplitudes of de Haas-van Alphen effect oscillations, which are well fitted by the Lifshitz-Kosevich (LK) formula across the measured temperature range, and those from SdH measurements which show a significant disagreement with LK behavior at low temperatures. Our findings of unusual quantum oscillations in an antiferromagnetic, mixed valence semimetal with a possible non-trivial band topology can provide an opportunity for studying the interplay between topology, electronic correlations and magnetism.

Tuning the nontrivial topological properties of the Weyl semimetal CeAlSi

“…This rare response of the oscillation amplitude as a function of temperature was not observed in other members of the LnAlP n family so far [31,33,35,41]. It was previously observed in just a few materials, such as the chargetransfer salts [58] and SmSb [59]. In the first case, the sudden decrease of the amplitude with decreasing temperature was associated with the presence of highly metallic edge states related to the quantum Hall effect in quasi-two-dimensional materials [58], which is unlikely to be the cause for the behavior found in CeAlSi.…”

“…In the first case, the sudden decrease of the amplitude with decreasing temperature was associated with the presence of highly metallic edge states related to the quantum Hall effect in quasi-two-dimensional materials [58], which is unlikely to be the cause for the behavior found in CeAlSi. In the latter system, a sudden decrease of the Shubnikov-de Haas oscillations takes place once the material becomes antiferromagnetic, which could be caused by a nontrivial Berry phase [59]. Similarly to CeAlSi, the unusual behavior of the QO amplitude also appears in connection with a magnetically ordered phase.…”

Anisotropic and extreme magnetoresistance in the magnetic semimetal candidate erbium monobismuthide

“…Recent attention is given to the NaCl-type rare-earth monopnictide RPn (R = rare earth; Pn = Sb, Bi) family [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26], which are predicted to be promising correlated topological semimetal candidates [24,27]. RPn are always identified as compensated semimetals in the electronic structure aspect, where the conduction and valence bands are constituted by the 5d t 2g state of R and 3/2 p state of Pn, and lie at the X and points in the first Brillouin zone, respectively [28].…”

Magnetotransport and electronic structure of the antiferromagnetic semimetal YbAs

“…Searching for correlated and magnetic materials with topologically non-trivial electronic structures has recently led to the discovery of novel topological phases, such as topological Kondo insulators [1,2], magnetic topological insulators [3][4][5][6], magnetic Weyl semimetals [7][8][9][10] and Weyl-Kondo semimetals [11,12]. The LnX series crystallizing in the cubic NaCl-type structure [13](Ln = rare-earth and X = As, Sb or Bi) is a large family of semimetals where topologically nontrivial band structures have been found to exist with electronic correlations and magnetism [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. For example, evidence was found that CeSb hosts Weyl fermions in the fieldinduced ferromagnetic state [14], while NdSb was reported to be a Dirac semimetal with antiferromagnetic (AFM) order [25][26][27].…”

“…For example, evidence was found that CeSb hosts Weyl fermions in the fieldinduced ferromagnetic state [14], while NdSb was reported to be a Dirac semimetal with antiferromagnetic (AFM) order [25][26][27]. Meanwhile in SmSb, the analysis of the Shubnikov-de Haas (SdH) oscillations indicates a topologically non-trivial band structure [29]. Topological electronic structures were detected using angle-resolved photoemission spectroscopy (ARPES) for several rareearth mono-bismuthides (Ce, Pr, Sm, Gd)Bi, showing tunable bulk band inversions and corresponding surface states [30], where the ARPES results agree well with density functional theory (DFT) calculations assuming the 4f -electrons to be well localized [32].…”