TY - JOUR
T1 - Effect of Pt vacancies on magnetotransport of Weyl semimetal candidate GdPtSb epitaxial films
AU - Du, Dongxue
AU - Thoutam, Laxman Raju
AU - Genser, Konrad T.
AU - Zhang, Chenyu
AU - Rabe, Karin M.
AU - Samanta, Tamalika
AU - Jung, Taehwan
AU - Jalan, Bharat
AU - Voyles, Paul M.
AU - Kawasaki, Jason K.
N1 - Publisher Copyright:
© 2023 American Physical Society.
PY - 2023/8
Y1 - 2023/8
N2 - We examine the effects of Pt vacancies on the magnetotransport properties of Weyl semimetal candidate GdPtSb films, grown by molecular beam epitaxy on c-plane sapphire. Rutherford backscattering spectrometry and x-ray diffraction measurements suggest that phase-pure GdPtxSb films can accommodate up to 15% of Pt vacancies (x=0.85), which act as acceptors, as measured by the Hall effect. Two classes of electrical transport behavior are observed. Pt-deficient films display metallic temperature-dependent resistivity (dρ/dT>0). The longitudinal magnetoresistance (LMR, magnetic field B parallel to electric field E) is more negative than transverse magnetoresistance (TMR, B⊥E), consistent with the expected chiral anomaly for a Weyl semimetal. The combination of Pt-vacancy disorder and doping away from the expected Weyl nodes, however, suggests that conductivity fluctuations may explain the negative LMR rather than chiral anomaly. Samples closer to stoichiometry display the opposite behavior: semiconductorlike resistivity (dρ/dT>0) and more negative TMR than LMR. Hysteresis and other nonlinearities in the low-field Hall effect and magnetoresistance suggest that spin-disorder scattering and possible topological Hall effect may dominate the near-stoichiometric samples. Our findings highlight the complications of transport-based identification of Weyl nodes but point to possible topological spin textures in GdPtSb.
AB - We examine the effects of Pt vacancies on the magnetotransport properties of Weyl semimetal candidate GdPtSb films, grown by molecular beam epitaxy on c-plane sapphire. Rutherford backscattering spectrometry and x-ray diffraction measurements suggest that phase-pure GdPtxSb films can accommodate up to 15% of Pt vacancies (x=0.85), which act as acceptors, as measured by the Hall effect. Two classes of electrical transport behavior are observed. Pt-deficient films display metallic temperature-dependent resistivity (dρ/dT>0). The longitudinal magnetoresistance (LMR, magnetic field B parallel to electric field E) is more negative than transverse magnetoresistance (TMR, B⊥E), consistent with the expected chiral anomaly for a Weyl semimetal. The combination of Pt-vacancy disorder and doping away from the expected Weyl nodes, however, suggests that conductivity fluctuations may explain the negative LMR rather than chiral anomaly. Samples closer to stoichiometry display the opposite behavior: semiconductorlike resistivity (dρ/dT>0) and more negative TMR than LMR. Hysteresis and other nonlinearities in the low-field Hall effect and magnetoresistance suggest that spin-disorder scattering and possible topological Hall effect may dominate the near-stoichiometric samples. Our findings highlight the complications of transport-based identification of Weyl nodes but point to possible topological spin textures in GdPtSb.
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U2 - 10.1103/PhysRevMaterials.7.084204
DO - 10.1103/PhysRevMaterials.7.084204
M3 - Article
AN - SCOPUS:85172934456
SN - 2475-9953
VL - 7
JO - Physical Review Materials
JF - Physical Review Materials
IS - 8
M1 - 084204
ER -