Point-contact Andreev reflection spectroscopy on Bi<sub>2</sub>Se<sub>3</sub> single crystals

Granstrom, C. R.; Fridman, I.; Lei, Hechang; Petrović, C.; Wei, J.Y.T.

doi:10.1142/s0217979216420029

Cited by 3 publications

(3 citation statements)

References 32 publications

(33 reference statements)

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“…see Ref. [43]). In any case, the peak separation is 6-8 mV for both NbO x tip-YBCO sample and YBCO tip-NbO x sample combinations, indicating that it is not sensitive to sample preparation procedure.…”

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confidence: 95%

“…These measurements were made using a home-built 4 He dipper-probe scanning tunneling microscope (STM), designed to allow tip and sample loading within a glovebox filled with dry N 2 gas. Measurement electronics are described elsewhere [23,43]. XPS measurements were performed with a PHI 5500 analytical chamber using monochromated Al K α radiation of 1486.7 eV at a take-off angle of 75 • (for details see Ref.…”

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confidence: 99%

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Probing itinerant antiferromagnetism with $d$-wave Andreev reflection spectroscopy

Granstrom¹,

Liang²,

Li³

et al. 2018

Preprint

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To study how Andreev reflection (AR) is affected by itinerant antiferromagnetism, we perform dwave AR spectroscopy with superconducting YBa2Cu3O 7−δ on TiAu and on variously-oxidized Nb (NbOx) samples. X-ray photoelectron spectroscopy is also used on the latter to measure their surface oxide composition. Below the Néel temperatures (TN ) of both TiAu and NbOx, the conductance spectra show a dip-like structure instead of a zero-bias peak within the superconducting energy gap; for NbOx, higher-oxidized samples show a stronger spectral dip at zero bias. These observations indicate that itinerant antiferromagnetic order suppresses the AR process. Interestingly, the spectral dip persists above TN for both TiAu and NbOx, implying that spin fluctuations can also suppress AR. Our results suggest that d-wave AR spectroscopy may be used to probe the degree of spin ordering in itinerant antiferromagnets.

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confidence: 95%

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confidence: 99%

Probing itinerant antiferromagnetism with $d$-wave Andreev reflection spectroscopy

Granstrom¹,

Liang²,

Li³

et al. 2018

Preprint

Self Cite

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“…Point contact Andreev reflection (PCAR) spectroscopy, now a well established technique, was successfully applied to measure the spin-polarization of elemental ferromagnets, like Fe, Co, Ni [25] and ferromagnetic compounds like SrRuO 3 [27], CuFeSb [28] etc. Recently it was shown that PCAR spectroscopy using a superconducting tip on the surface of a topological insulator can also be employed for measuring the transport spin-polarization in TIs [29][30][31]. This was demonstrated by Borisov et al where they measured spin-polarization of Bi 2 Te 3 to be 70% which is remarkably higher than the known ferromagnetic metals [29].…”

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Suppression of transport spin-polarization of surface states with emergence of ferromagnetism in Mn-doped Bi₂Se₃

Kamboj

Das

Sirohi

et al. 2018

J. Phys.: Condens. Matter

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The surface states of topological insulators (TI) are protected by time reversal symmetry and they display intrinsic spin helicity where the momentum of the charge carriers decides their spin states. As a consequence, a current injected through the surface states becomes spin polarized and this transport spin-polarization leads to a proportionate suppression of Andreev reflection in superconductor/TI junctions. Here we show that upon doping BiSe with Mn, the transport spin-polarization is seen to be monotonically suppressed. The parent compound BiSe is found to exhibit a transport spin-polarization of about 63% whereas crystals with 10% Mn doping show transport spin-polarization of about 48%. This suppression is accompanied by an increasing ferromagnetic order of the crystals with Mn doping. Scanning tunneling spectroscopy shows that the topological protection of the surface states reduces due to Mn doping. The net measured transport spin-polarization is due to a competition of this effect with the increased magnetization on Mn doping. The present results provide important insights for the choice of magnetic topological insulators for spintronic applications.

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High Fermi-level spin polarization in the(Bi1−xSbx)2Te3family of topological insulators: A point contact Andreev refle

et al. 2016

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Point contact Andreev reflection spectroscopy is employed to extract the effective Fermi-level spin polarization of three distinct compositions from the (Bi 1−x Sb x ) 2 Te 3 topological insulator family. The end members, Bi 2 Te 3 and Sb 2 Te 3 , exhibit high polarization of 70(4)% and 57(3)%, respectively. High-field (μ 0 H = 14 T) point contact spectroscopy shows carrier depletion close to the Fermi level for these two compositions with small activation gaps of 0.40(4) and 0.28 (2)

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Point-contact Andreev reflection spectroscopy on Bi₂Se₃ single crystals

Cited by 3 publications

References 32 publications

Probing itinerant antiferromagnetism with $d$-wave Andreev reflection spectroscopy

Probing itinerant antiferromagnetism with $d$-wave Andreev reflection spectroscopy

Suppression of transport spin-polarization of surface states with emergence of ferromagnetism in Mn-doped Bi₂Se₃

High Fermi-level spin polarization in the(Bi1−xSbx)2Te3family of topological insulators: A point contact Andreev refle

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Point-contact Andreev reflection spectroscopy on Bi2Se3 single crystals

Cited by 3 publications

References 32 publications

Probing itinerant antiferromagnetism with $d$-wave Andreev reflection spectroscopy

Probing itinerant antiferromagnetism with $d$-wave Andreev reflection spectroscopy

Suppression of transport spin-polarization of surface states with emergence of ferromagnetism in Mn-doped Bi2Se3

High Fermi-level spin polarization in the(Bi1−xSbx)2Te3family of topological insulators: A point contact Andreev refle

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Point-contact Andreev reflection spectroscopy on Bi₂Se₃ single crystals

Suppression of transport spin-polarization of surface states with emergence of ferromagnetism in Mn-doped Bi₂Se₃