Reduction of bulk carrier concentration in Bridgman-grown Bi 2 Se 3 topological insulator by crystallization with Se excess and Ca doping

Hruban, A.; Strzelecka, S.; Materna, A.; Wołoś, Agnieszka; Jurkiewicz-Wegner, E.; Piersa, M.; Orłowski, Witold M.; Dalecki, W.; Kamińska, M.; Romaniec, M.

doi:10.1016/j.jcrysgro.2014.08.026

Cited by 10 publications

(12 citation statements)

References 13 publications

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“…3, 4 and 5 give a quantitative idea for the order of magnitude of H stag , in reality the electronic scattering rate and the carrier density are not independent variables. In order to obtain more reliable results, we take the carrier densities and resistivities provided by various experiments, [17][18][19][20][21][22] and from there calculate the staggered field. The outcome is shown in Fig.…”

Section: A Resultsmentioning

confidence: 99%

NMR in an electric field: A bulk probe of the hidden spin and orbital polarizations

2017

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Recent theoretical work has established the presence of hidden spin and orbital textures in nonmagnetic materials with inversion symmetry. Here, we propose that these textures can be detected by nuclear magnetic resonance (NMR) measurements carried out in the presence of an electric field. In crystals with hidden polarizations, a uniform electric field produces a staggered magnetic field that points to opposite directions at atomic sites related by spatial inversion. As a result, the NMR resonance peak corresponding to inversion partner nuclei is split into two peaks. The magnitude of the splitting is proportional to the electric field and depends on the orientation of the electric field with respect to the crystallographic axes and the external magnetic field. As a case study, we present a theory of electric-field-induced splitting of NMR peaks for 77 Se, 125 Te and 209 Bi in Bi2Se3 and Bi2Te3. In conducting samples with current densities of 10 6 A/cm 2 , the splitting for Bi can reach 100 kHz, which is comparable to or larger than the intrinsic width of the NMR lines. In order to observe the effect experimentally, the peak splitting must also exceed the linewidth produced by the Oersted field. In Bi2Se3, this requires narrow wires of radius 1 µm. We also discuss other potentially more promising candidate materials, such as SrRuO3 and BaIr2Ge2, whose crystal symmetry enables strategies to suppress the linewidth produced by the Oersted field. arXiv:1709.02376v2 [cond-mat.mtrl-sci]

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Section: A Resultsmentioning

confidence: 99%

NMR in an electric field: A bulk probe of the hidden spin and orbital polarizations

2017

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“…The growth details can be found in Ref. [13]. The crystal growth process consisted of the following three stages: synthesis, directional crystallization and annealing.…”

Section: Samples and The Experimentsmentioning

confidence: 99%

“…Therefore, undoped Bi 2 Se 3 is typically n-type with actual electron concentration strongly dependent on growth conditions. In the Bridgman growth method, the electron concentration can be effectively controlled by varying the stoichiometry of the melt [13]. Crystals grown from the stoichiometric melt show room-temperature electron concentration as high as 10 19 -10 20 cm À 3 , while increasing the selenium-to-bismuth ratio lowers the electron concentration to $10 17 cm À 3 .…”

Section: Samples and The Experimentsmentioning

confidence: 99%

“…This approach has shown to be a compromise between lower electron concentration of the base (undoped) material and good crystal morphology (avoiding Se precipitation). It has also led us to a successful doping with another acceptor (Ca) [13]. Table 1 shows the growth conditions of Mn-doped Bi 2 Se 3 versus its carrier concentration (at room temperature).…”

Section: Samples and The Experimentsmentioning

confidence: 99%

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High-spin configuration of Mn in Bi2Se3 three-dimensional topological insulator

Wołoś

Drabińska

Borysiuk

et al. 2016

Journal of Magnetism and Magnetic Materials

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“…Bi 2 Se 3 can be synthetized as bulk crystals, thin films or nanoparticles by several methods 15 . Bulk crystals have been synthetized by Bridgman–Stockbarger 16 , flux 17 and other methods, and then chemically or mechanically exfoliated to study their properties as thin films 18 . Excellent results have been achieved this way.…”

Section: Introductionmentioning

confidence: 99%

Self-assembled Bismuth Selenide (Bi2Se3) quantum dots grown by molecular beam epitaxy

Claro

Levy

Gangopadhyay

et al. 2019

Sci Rep

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We report the growth of self-assembled Bi 2 Se 3 quantum dots (QDs) by molecular beam epitaxy on GaAs substrates using the droplet epitaxy technique. The QD formation occurs after anneal of Bismuth droplets under Selenium flux. Characterization by atomic force microscopy, scanning electron microscopy, X-ray diffraction, high-resolution transmission electron microscopy and X-ray reflectance spectroscopy is presented. Raman spectra confirm the QD quality. The quantum dots are crystalline, with hexagonal shape, and have average dimensions of 12-nm height (12 quintuple layers) and 46-nm width, and a density of 8.5 × 10 9 cm −2 . This droplet growth technique provides a means to produce topological insulator QDs in a reproducible and controllable way, providing convenient access to a promising quantum material with singular spin properties.

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Reduction of bulk carrier concentration in Bridgman-grown Bi 2 Se 3 topological insulator by crystallization with Se excess and Ca doping

Cited by 10 publications

References 13 publications

NMR in an electric field: A bulk probe of the hidden spin and orbital polarizations

NMR in an electric field: A bulk probe of the hidden spin and orbital polarizations

High-spin configuration of Mn in Bi2Se3 three-dimensional topological insulator

Self-assembled Bismuth Selenide (Bi2Se3) quantum dots grown by molecular beam epitaxy

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