Seminarium Oddziału Badań Magnetyków
Microsoft Teams
Effect of electron irradiation on the magnetotransport properties of half-Heusler topological semimetal candidates
dr Orest Pavlosiuk
Oddział Badań Magnetyków INTiBS PAN
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Streszczenie:
Half-Heusler materials are among one of the most intensively investigated families of topological materials. Over a decade ago, several half-Heusler compounds have been proposed to be topological materials [1], and interest in this group of materials continues to grow. Recently, it has been proposed that half-Heusler compound GdPtBi is the first example of a topological Weyl semimetal in which Weyl nodes are induced by external magnetic field [2]. The existence of Weyl states in this material has been confirmed by the observation of negative longitudinal magnetoresistance and anomalous Hall effect [2, 3]. In half-Heusler phase YPtBi, the existence of topologically non-trivial states has been confirmed by angle-resolved photoemission spectroscopy [4, 5], however, no strong evidence of topologically non-trivial states has been observed in electron transport properties.
In this study, we tuned the Fermi level in GdPtBi and YPtBi single crystals, in order to find what effect this has on the electron transport properties of these materials. High-energy electron irradiation technique was used to tune the Fermi level. Single crystals of both materials were irradiated with several doses from the range between 1.5 and 6 C/cm2. Electron transport properties (electrical resistivity, magnetoresistance and Hall effect) were examined for all irradiated and pristine samples. The results of Hall effect measurements showed that carrier concentration increases with increasing irradiation dose for both samples, confirming the Fermi level shift. We found that as the irradiation dose increases, the absolute values of transverse and longitudinal magnetoresistance decrease for both materials. This could mean that the contribution of the chiral magnetic anomaly to the longitudinal magnetoresistance of GdPtBi becomes smaller as the irradiation dose increases. Interestingly, we discovered that the magnetic field at which the anomalous Hall effect in GdPtBi riches its maximum also changes with the irradiation dose.
[1] H. Lin et al., Nat. Mat. 9, 546 (2010).
[2] M. Hirschberger et al., Nat. Mater. 15, 1161 (2016).
[3] C. Shekhar et al., PNAS 115, 9140 (2018).
[4] Z. K. Liu et al., Nat. Commun. 7, 12924 (2016).
[5] M. M. Hosen et al., Sci. Rep. 10, 12343 (2020).