Distinct effects of Cr bulk doping and surface deposition on the chemical environment and electronic structure of the topological insulator Bi2Se3

Yilmaz, Turgut; Hines, W. A.; Sun, Fu-Chang; Pletikosić, Ivo; Budnick, J. I.; Valla, T.; Sinković, B.

doi:10.1016/j.apsusc.2017.02.160

Cited by 12 publications

(10 citation statements)

References 37 publications

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“…Obviously, more than 1.5% of Cr bulk doping in the place of Bi would destruct the Dirac surface state. In our case, the size of the energy gap was 85 meV, which is comparable to other Cr and V doped Bi 2 Se 3 magnetic topological insulator for x>0.10 concentration [31,32]. This energy gap resides ∼130 meV from a Fermi level and the momentum broadening of the surface state is also seen by a bulk doping effect.…”

Section: Resultssupporting

confidence: 70%

“…The spin-orbit coupling strength gradually varied from Bi (4 f) to Cr (2p) as a consequence of the blue shift between them as well as large splitting of binding energy levels (∼9 eV) rather than Cr-Se bond contribution was observed [14]. From XPS, the electron doping effect on the surface caused by a residual atmospheric gas molecule absorption plays the major role for inducing charge transfer effect [32].…”

Section: Resultsmentioning

confidence: 99%

“…Similarly, chromium 3 + oxidations peaks can also be fitted for the 2p binding energy levels of 585.2 eV and 575.3 eV. 32 We see that the atomic concentration values of Cr ∼1.5% for Bi 2−x Cr x Se 3 and Te ∼10.5% in Bi 2 Se 3−y Te y at the initial peaks of Bi (4 f), Cr (2p), Se (3d), Te (3d) binding energy levels. From Bi 2 Se 3 core level XPS spectra, the top layered Bi (4 f) and Se (3d) peaks are strongly red shifts (more than 1.3 eV) to 156.7 eV and 51.8 eV.…”

Section: Resultsmentioning

confidence: 99%

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Topological quantum weak antilocalization limit and anomalous Hall effect in semimagnetic Bi_2−xCr_xSe₃/Bi₂Se_3−yTey heterostructure

Kanagaraj

Sun

Ning

et al. 2019

Mater. Res. Express

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Magnetic topological insulator hosts both a non-trivial surface band and quantum anomalous Hall effect when tuning the time reversal symmetry by various chemical doping into the system. Using molecular beam epitaxy, we have synthesized Bi 2−x Cr x Se 3 /Bi 2 Se 3−y Te y heterostructure, which was scrutinized via in situ angle resolved photoemission spectroscopy, ex situ x-ray diffraction, Raman, and x-ray photoemission characteristics analyzing techniques. We used the Hikami-Larkin-Nagaoka formula for quantifying the weak antilocalization limit in Bi 2−x Cr x Se 3 and Bi 2 Se 3−y Te y non-magnetic layer coupling near the ferromagnetic transition temperature (∼7 K). A higher concentration of Cr (1.5%) in Bi site leads to bulk carrier density for entire cooling temperature with a bandgap of 85 meV. The proximity effect of Te doped Bi 2 Se 3 with magnetic topological insulator degrades the ferromagnetic response for this heterostructure. Our study suggests that the manipulation of disorder free magnetic top layer and fine tuning of spin-orbit coupling strength in the bottom topological insulator can be helpful to understand the high temperature quantum anomalous Hall effect towards relativistic quantum electronics applications.

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Section: Resultssupporting

confidence: 70%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Topological quantum weak antilocalization limit and anomalous Hall effect in semimagnetic Bi_2−xCr_xSe₃/Bi₂Se_3−yTey heterostructure

Kanagaraj

Sun

Ning

et al. 2019

Mater. Res. Express

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“…In previous literature, new component in the spectra of Bi 5d core level has been detected when Cr [31], Fe [10], Pd, Ir, Co, CoFe, Ni, Cr, NiFe , Fe and Au [16] were deposited at room temperature on Bi2Se3. The new component of Bi 5d detected upon metals adsorption, was reported to be in the range of 0.75 eV -1 eV lower BE with respect to the component of clean Bi2Se3 (Bi 3+ ).…”

Section: Resultsmentioning

confidence: 92%

Growth, morphology and stability of Au in contact with the Bi2Se3(0 0 0 1) surface

Fanetti

Mikulska

Ferfolja

et al. 2019

Applied Surface Science

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Highlights Au evaporated on Bi2Se3 at RT forms islands according to the Volmer-Weber growth mode  upon annealing to 100° C the Au deposits are not stable and assemble into larger and thicker islands  the Topological surface state (TSS) of Bi2Se3 is weakly affected by the presence of Au  at the Au/Bi2Se3 interface there is a weak chemical instability that results in Bi diffusion toward the surface of Au islands and in a chemical interaction between Au and atomic Se limited at the interfacial region  for the investigated range of Au coverages, the Au/Bi2Se3 heterostructure is inert towards CO and CO2 exposure at low pressure (10 -8 mbar) regime AbstractWe report a combined microscopy and spectroscopy study of Au deposited on the Bi2Se3 (0001) single crystal surface. At room temperature Au forms islands, according to the Volmer-Weber growth mode. Upon annealing to 100° C the Au deposits are not stable and assemble into larger and thicker islands. The topological surface state of Bi2Se3 is weakly affected by the presence of Au. Contrary to other metals, suchas Ag or Cr, a strong chemical instability at the Au/Bi2Se3 interface is ruled out. Core level analysis highlights Bi diffusion toward the surface of Au islands, in agreement with previous findings, while chemical interaction between Au and atomic Se is limited at the interfacial region. For the investigated range of Au coverages, the Au/Bi2Se3 heterostructure is inert towards CO and CO2 exposure at low pressure (10 -8 mbar) regime.

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“…However, due to high density of ntype native defects, the Fermi levels of common Bi2Se3 are always far from the Dirac point and frequently above the bulk conduction band minimum, making the bulk metallic. [5][6][7][8][9][10] In order to fully utilize all the intriguing properties of the topological surface states, it is essential to find a way to tune the Fermi level, not only toward the Dirac point but also into the p-regime as well. In case of Bi2Se3, substituting a 2+ ion for Bi 3+ is one of the most obvious ways to reduce the n-type carriers and move toward the p-regime.…”

mentioning

confidence: 99%

Pb-doped p -type Bi2Se3 thin films via interfacial engineering

Moon

Huang

et al. 2020

Phys. Rev. Materials

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Due to high density of native defects, the prototypical topological insulator (TI), Bi2Se3, is naturally n-type. Although Bi2Se3 can be converted into p-type by substituting 2+ ions for Bi, only light elements such as Ca have been so far effective as the compensation dopant. Considering that strong spinorbit coupling (SOC) is essential for the topological surface states, a light element is undesirable as a dopant, because it weakens the strength of SOC. In this sense, Pb, which is the heaviest 2+ ion, located right next to Bi in the periodic table, is the most ideal p-type dopant for Bi2Se3. However, Pb-doping has so far failed to achieve p-type Bi2Se3 not only in thin films but also in bulk crystals. Here, by utilizing an interface engineering scheme, we have achieved the first Pb-doped p-type Bi2Se3 thin films. Furthermore, at heavy Pb-doping, the mobility turns out to be substantially higher than that of Ca-doped samples, indicating that Pb is a less disruptive dopant than Ca. With this SOC-preserving counter-doping scheme, it is now possible to fabricate Bi2Se3 samples with tunable Fermi levels without compromising their topological properties.

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Distinct effects of Cr bulk doping and surface deposition on the chemical environment and electronic structure of the topological insulator Bi2Se3

Cited by 12 publications

References 37 publications

Topological quantum weak antilocalization limit and anomalous Hall effect in semimagnetic Bi_2−xCr_xSe₃/Bi₂Se_3−yTey heterostructure

Topological quantum weak antilocalization limit and anomalous Hall effect in semimagnetic Bi_2−xCr_xSe₃/Bi₂Se_3−yTey heterostructure

Growth, morphology and stability of Au in contact with the Bi2Se3(0 0 0 1) surface

Pb-doped p -type Bi2Se3 thin films via interfacial engineering

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Distinct effects of Cr bulk doping and surface deposition on the chemical environment and electronic structure of the topological insulator Bi2Se3

Cited by 12 publications

References 37 publications

Topological quantum weak antilocalization limit and anomalous Hall effect in semimagnetic Bi2−xCrxSe3/Bi2Se3−yTey heterostructure

Topological quantum weak antilocalization limit and anomalous Hall effect in semimagnetic Bi2−xCrxSe3/Bi2Se3−yTey heterostructure

Growth, morphology and stability of Au in contact with the Bi2Se3(0 0 0 1) surface

Pb-doped p -type Bi2Se3 thin films via interfacial engineering

Contact Info

Product

Resources

About

Topological quantum weak antilocalization limit and anomalous Hall effect in semimagnetic Bi_2−xCr_xSe₃/Bi₂Se_3−yTey heterostructure

Topological quantum weak antilocalization limit and anomalous Hall effect in semimagnetic Bi_2−xCr_xSe₃/Bi₂Se_3−yTey heterostructure

Growth, morphology and stability of Au in contact with the Bi2Se3(0 0 0 1) surface