Bulk band structure of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">Bi</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">Te</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math>

Michiardi, Matteo; Aguilera, Irene; Bianchi, Marco; Carvalho, V. E. de; Ladeira, Luiz Orlando; Teixeira, Nayara Gomes; Soares, E.A.; Friedrich, Christoph; Blügel, Stefan; Hofmann, Philip

doi:10.1103/physrevb.90.075105

Cited by 71 publications

(68 citation statements)

References 47 publications

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“…The main reason is that, as seen in the ARPES data 6,50 , the electrons populate first the conduction band states located at the Γ point or along the Γ-Z line 53 that lie at a smaller energy than those along the Z-F line. As a consequence, the minimum excitation energy is not increased for weakly doped samples.…”

Section: B the Absorption Edge In Bi2se3mentioning

confidence: 99%

“…Obviously, the onset occurs at a different point in the Brillouin zone. Bandstructure calculations 45,[51][52][53] indeed suggest that the direct gap should be close to the Z-F line in the Brillouin zone, where the interband transition energy is significantly smaller than that at the Γ point. The bandgap values have been treated theoretically in detail in Ref.…”

Section: B the Absorption Edge In Bi2se3mentioning

confidence: 99%

“…As suggested by bandstructure calculations, the direct transition occurs near the Z-F line in the Brillouin zone. Since along the Γ-Z line the energy of the conduction band lies at lower energy than along the Z-F line as suggested by the bandstructure calculations and ARPES 52,53 , there should be an indirect bandgap with an energy even lower than 170 meV, i.e., Bi 2 Te 3 is an indirect semiconductor. However, these indirect transitions are masked in our data by the much stronger response of free charge carriers that yields of about 5 for ε 2 below E direct g .…”

Section: B the Absorption Edge In Bi2se3mentioning

confidence: 99%

“…On the Bi 2 Te 3 side shown in Fig. 9(c), the direct bandgap occurs off the Brillouine zone centre near the Z-F line, between the wing of the M-shaped valence band and a conduction band 52,53 . The green arrow depicts the indirect fundamental gap which, however, has orders of magnitude lower absorption and therefore is masked in our data by the much stronger free charge carriers response.…”

Section: B the Absorption Edge In Bi2se3mentioning

confidence: 99%

“…According to the GW calculations 52,53 , the structure of the calculated valence and conduction band along the Z-F line is rather complicated; it seems to have several extrema. It is possible that with changing temperature, the position of the lowest direct bandgap changes and at low temperature, an interband transition with a smaller joint density of states compared to the main one sets in and gives rise to the observed onset at 170 meV.…”

Section: B the Absorption Edge In Bi2se3mentioning

confidence: 99%

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Interband absorption edge in the topological insulators Bi2(Te1−xSex)3

et al. 2017

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We have investigated the optical properties of thin films of topological insulators Bi2Te3, Bi2Se3 and their alloys Bi2(Te1−xSex)3 on BaF2 substrates by a combination of infrared ellipsometry and reflectivity in the energy range from 0.06 to 6.5 eV. For the onset of interband absorption in Bi2Se3, after the correction for the Burstein-Moss effect, we find the value of direct bandgap of 215±10 meV at 10 K. Our data supports the picture that Bi2Se3 has a direct band gap located at the Γ point in the Brillouin zone and that the valence band reaches up to the Dirac point and has the shape of a downward oriented paraboloid, i.e. without a camel-back structure. In Bi2Te3, the onset of strong direct interband absorption at 10 K is at a similar energy of about 200 meV, with a weaker additional feature at about 170 meV. Our data support the recent GW band structure calculations suggesting that the direct interband transition does not occur at the Γ point but near the Z-F line of the Brillouin zone. In the Bi2(Te1−xSex)3 alloy, the energy of the onset of direct interband transitions exhibits a maximum near x = 0.3 (i.e. the composition of Bi2Te2Se), suggesting that the crossover of the direct interband transitions between the two points in the Brillouin zone occurs close to this composition.

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Section: B the Absorption Edge In Bi2se3mentioning

confidence: 99%

Section: B the Absorption Edge In Bi2se3mentioning

confidence: 99%

Section: B the Absorption Edge In Bi2se3mentioning

confidence: 99%

Section: B the Absorption Edge In Bi2se3mentioning

confidence: 99%

Section: B the Absorption Edge In Bi2se3mentioning

confidence: 99%

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Interband absorption edge in the topological insulators Bi2(Te1−xSex)3

et al. 2017

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Many‐Body Effects in the Electronic Structure of Topological Insulators

Aguilera

Nechaev

Friedrich

et al. 2015

Topological Insulators

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IntroductionMost of the calculations present in the literature for topological insulators (TIs) are based on model Hamiltonians or parameter-dependent tight-binding descriptions [1][2][3][4], and density functional theory (DFT) employing either the local density approximations (LDA) or generalized gradient approximations (GGA) [5][6][7][8][9][10][11][12][13]. Because of their efficiency, the LDA and GGA functionals have allowed for the study of surface and edge states of these materials [14][15][16][17][18][19], and they have shown mostly good agreement with the experimental results. However, LDA and GGA are approximations to the ground-state energy and cannot in principle be expected to yield accurate excited-state properties. More specifically, one often takes the single-particle states that solve the Kohn-Sham (KS) equation of DFT as approximate excitations energies. But these states, strictly speaking, are merely mathematical tools that cannot be endowed with a physical meaning. In particular, they suffer from a strong self-interaction error and lack many-body renormalization effects. Related to that, the DFT bandgap of insulators and semiconductors, though in fact being a ground-state property, is systematically underestimated [20][21][22]. TIs are not an exception: because of their inverted bandgaps, the DFT underestimation of the bandgaps has not only quantitative but also qualitative consequences, and it can even lead to the wrong prediction of some trivial insulators as TIs [23]. Recently, to overcome this problem, calculations [23-33] based on the approximation [34] for the self-energy have started to emerge in the theoretical study of TIs and have shown that not only a much better agreement of the bandgap (in nature and magnitude) but also an improvement in the effective masses and spin-orbit splittings is found when compared to experimental results.In TIs, a strong spin-orbit coupling (SOC) causes the top valence and the bottom conduction band to invert in the bandgap region. The bands hybridize so that an energy gap forms that is of the order of the spin-orbit strength (up to a few hundreds of millielectronvolts). Such small bandgaps require a reliable description of the electronic structure. The inverted band structure is often -but not always, Topological Insulators: Fundamentals and Perspectives, First Edition. Edited

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Surface Electronic Structure Engineering of Manganese Bismuth Tellurides Guided by Micro‐Focused Angle‐Resolved Photoemission

Volckaert,

Majchrzak,

Biswas

et al. 2023

Advanced Materials

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Modification of the electronic structure of quantum matter by ad atom deposition allows for directed fundamental design of electronic and magnetic properties. This concept is utilized in the present study in order to tune the surface electronic structure of magnetic topological insulators based on MnBi2Te4. The topological bands of these systems are typically strongly electron‐doped and hybridized with a manifold of surface states that place the salient topological states out of reach of electron transport and practical applications. In this study, micro‐focused angle‐resolved photoemission spectroscopy (microARPES) provides direct access to the termination‐dependent dispersion of MnBi2Te4 and MnBi4Te7 during in situ deposition of rubidium atoms. The resulting band structure changes are found to be highly complex, encompassing coverage‐dependent ambipolar doping effects, removal of surface state hybridization, and the collapse of a surface state band gap. In addition, doping‐dependent band bending is found to give rise to tunable quantum well states. This wide range of observed electronic structure modifications can provide new ways to exploit the topological states and the rich surface electronic structures of manganese bismuth tellurides.

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Bulk band structure ofBi2Te3

Cited by 71 publications

References 47 publications

Interband absorption edge in the topological insulators Bi2(Te1−xSex)3

Interband absorption edge in the topological insulators Bi2(Te1−xSex)3

Many‐Body Effects in the Electronic Structure of Topological Insulators

Surface Electronic Structure Engineering of Manganese Bismuth Tellurides Guided by Micro‐Focused Angle‐Resolved Photoemission

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