Infrared electrodynamics and ferromagnetism in the topological semiconductors<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:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">Te</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math>and Mn-doped<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></m

Chapler, B. C.; Post, Kirk; Richardella, Anthony; Lee, Joon Sue; Tao, Jing; Samarth, N.; Basov, D. N.

doi:10.1103/physrevb.89.235308

Cited by 24 publications

(29 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The frequencies of the α and β phonons (see Tab. I) compare well with reported values 11,15,19 . Between about 0.1-0.8 eV (see Fig.…”

Section: B the Optical Spectroscopy And Analysis Of Optical Datasupporting

confidence: 80%

“…The energy of this onset is the same as found in an earlier report of Sehr and Testardi 48 . Chapler et al 15 reported the onset of interband absorption in Bi 2 Te 3 thin films between 140-150 meV at 300 K not too different from our value of 157 meV. Their onset value did not exhibit a significant blue shift with cooling to 10 K. A direct gap was observed in Ref.…”

Section: B the Absorption Edge In Bi2se3supporting

confidence: 48%

“…Despite the large experimental effort, several questions remain open. For example controversial results on the values of the band gaps determined by optical spectroscopy and ARPES were reported 15,19 , raising questions about the actual position of the direct interband transition onset in the Brillouin zone. Here we present infrared spectroscopy study of Bi 2 (Te 1−x Se x ) 3 thin films that focuses on the absorption edge of interband transitions.…”

Section: Introductionmentioning

confidence: 99%

“…The infrared and optical response of Bi 2 (Te 1−x Se x ) 3 compounds have been intensively studied in order to characterize their vibrational properties 11 , interband absorption [12][13][14][15][16][17] and free charge carrier properties 14,[18][19][20] . Even the surface states [21][22][23][24] and strong Faraday rotation 25 have been observed by infrared spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

et al. 2017

View full text Add to dashboard Cite

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.

show abstract

“…The frequencies of the α and β phonons (see Tab. I) compare well with reported values 11,15,19 . Between about 0.1-0.8 eV (see Fig.…”

Section: B the Optical Spectroscopy And Analysis Of Optical Datasupporting

confidence: 80%

Section: B the Absorption Edge In Bi2se3supporting

confidence: 48%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

et al. 2017

View full text Add to dashboard Cite

show abstract

“…An insight into the band structure of the surface states of 3D TIs, especially proof for the single Dirac cone, is obtained by varios modifications of the angle resolved photoemission spectroscopy (ARPES) [26][27][28][29][30][31][32] , including spin-resolved and time-resolved ARPES, as well as by time-resolved two-photon photoelectron (2PPE) spectroscopy [33][34][35] , with which an enlightening pictures of fast dynamics in carrier relaxation can be obtained. Further methods, providing important information concerning different growth parameters, nucleation of trigonal islands, and domain alignment of the TI film with respect to the substrate, include scanning (STEM) and high angle annular dark field (HAADF) transmission electron microscopy [36][37][38][39] ; scanning electron microscope (SEM) 40 ; atomic force microscopy (AFM) 41 ; X-ray diffraction (XRD) 42 ; and second harmonic generation 43 as well as infrared or optical spectroscopy 44,45 . However, both spectroscopy and transport investigations do not allow one to analyze the local conductivity in particular at room temperature and materials homogeneity on a large scale.…”

mentioning

confidence: 99%

Opto-electronic characterization of three dimensional topological insulators

Plank

Danilov

Bel'kov

et al. 2016

Journal of Applied Physics

View full text Add to dashboard Cite

We demonstrate that the terahertz/infrared radiation induced photogalvanic effect, which is sensitive to the surface symmetry and scattering details, can be applied to study the high frequency conductivity of the surface states in (Bi1−xSbx)2Te3 based three dimensional (3D) topological insulators (TI). In particular, measuring the polarization dependence of the photogalvanic current and scanning with a micrometre sized beam spot across the sample, provides access to (i) topographical inhomogeneity's in the electronic properties of the surface states and (ii) the local domain orientation. An important advantage of the proposed method is that it can be applied to study TIs at room temperature and even in materials with a high electron density of bulk carriers.Electronic, optical and opto-electronic properties of topological insulators (TI) have attracted continuously growing attention yielding challenging fundamental concepts and being of potential interest for novel applications in the fields of spintronics and opto-electronics 1-5 . Hence, the fabrication of high quality topological insulators and their characterization yielding feedback to technologists is of particular importance. Until now a large variety of materials was proposed and confirmed to host topological protected surface states in three-dimensional (3D) TI and edge channels in two-dimensional (2D) TI. Particular examples are (Bi 1−x Sb x ) 2 Te 3 based 3D TI. Their fabrication in view of good insulating properties of the bulk at room temperature, homogeneity of a large area growth materials is still a challenging task. The former problem is caused by the high density of residual impurities serving parallel channels to the surface transport 6-8 . A promising way to overcome this problem serves the recent progress in growth of 3D TI applying molecular-beam-epitaxy (MBE) technique, see e.g., [9][10][11][12]. Owing to the progress in material growth, low temperature electron transport and magneto-transport studies becomes possible providing information on average electronic properties of Dirac fermions and carrier scattering mechanisms in 3D TIs 13-21 as well as to observe the quantum anomalous Hall effect reported for Cr or V doped (Bi 1−x Sb x ) 2 Te 3 based 3D TI 22-25 . An important issue for improvement of the material properties is their characterization allowing insights in the material properties and providing a feedback for technologists. For that a palette of methods has been developed and widely used. An insight into the band structure of the surface states of 3D TIs, especially proof for the single Dirac cone, is obtained by varios modifications of the angle resolved photoemission spectroscopy (ARPES) 26-32 , including spin-resolved and time-resolved ARPES, as well * permanent address: Ioffe Physical-Technical Institute, St. Petersburg, Russia † permanent address: Saint-Petersburg State Polytechnic University, St. Petersburg, Russia as by time-resolved two-photon photoelectron (2PPE) spectroscopy [33][34][35] , with which an enlightening pi...

show abstract

The feasibility analysis of growing the modified borophene on substrates: First-principles calculation

Xie

Wang

2020

Applied Surface Science

View full text Add to dashboard Cite

Infrared electrodynamics and ferromagnetism in the topological semiconductorsBi2Te3and Mn-dopedBi2

Cited by 24 publications

References 68 publications

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

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

Opto-electronic characterization of three dimensional topological insulators

The feasibility analysis of growing the modified borophene on substrates: First-principles calculation

Contact Info

Product

Resources

About