Brillouin Light Scattering Studies of Topological Insulators Bi2Se3, Sb2Te3, and Bi2Te3 PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Brillouin Light Scattering Studies of Topological Insulators Bi2Se3, Sb2Te3, and Bi2Te3 PDF full book. Access full book title Brillouin Light Scattering Studies of Topological Insulators Bi2Se3, Sb2Te3, and Bi2Te3 by Jamal Najr Alnofiay. Download full books in PDF and EPUB format.
Author: Jamal Najr Alnofiay Publisher: ISBN: Category : Languages : en Pages :
Book Description
Brillouin Light Scattering has been used to examine acoustic waves in three different Topological Insulators: Bismuth Selenide Bi2Se3, Antimony Telluride Sb2Te3, and Bismuth Telluride Bi2Te3. Two samples of each material were studied to ensure the accuracy of the results obtained. In general, surface mode, quasi-transverse, and quasi-longitudinal bulk modes were observed in all these materials. Rayleigh surface phonon velocities were obtained for the first time from the corresponding Brillouin peak frequency shifts. Quasi-transverse and quasi-longitudinal bulk mode velocities were also obtained. Elastic constants C33 and C44 were calculated from the measured bulk-velocities. Both bulk acoustic phonon velocities and elastic constants were compared to those obtained in previous studies. All results obtained have been found to be in good agreement with both experimental and some theoretical available studies.
Author: Jamal Najr Alnofiay Publisher: ISBN: Category : Languages : en Pages :
Book Description
Brillouin Light Scattering has been used to examine acoustic waves in three different Topological Insulators: Bismuth Selenide Bi2Se3, Antimony Telluride Sb2Te3, and Bismuth Telluride Bi2Te3. Two samples of each material were studied to ensure the accuracy of the results obtained. In general, surface mode, quasi-transverse, and quasi-longitudinal bulk modes were observed in all these materials. Rayleigh surface phonon velocities were obtained for the first time from the corresponding Brillouin peak frequency shifts. Quasi-transverse and quasi-longitudinal bulk mode velocities were also obtained. Elastic constants C33 and C44 were calculated from the measured bulk-velocities. Both bulk acoustic phonon velocities and elastic constants were compared to those obtained in previous studies. All results obtained have been found to be in good agreement with both experimental and some theoretical available studies.
Author: Kolawole Akintola Publisher: ISBN: Category : Languages : en Pages :
Book Description
Raman and Brillouin spectroscopy have been employed to investigate the phonon dynamics of Bi2Se3, Bi2Te3, Sb2Te3 (all topological insulators) and WSe2 (a 2D semiconductor). In the frequency range studied, two peaks were observed in the Raman spectra of Bi2Se3, Bi2Te3, Sb2Te3. Polarization studies were done to study the nature of these peaks and assign them to particular vibrational modes. Due to the fact that all three materials belong to the same space group and have the same Wycko↵ positions, it stands to reason that their Raman spectra will be identical in every respect except for the position where the peaks appear. This was found only to be partially true from what we observed. The presence of Te atoms in Bi2Te3, and Sb2Te3 was observed to play a prominent role in determining mode intensity. We verified that the higher intensity of the peak observed due to the A1g(2) 1g mode compared to that due to the Eg(2) g mode in Bi2Te3, and Sb2Te3, is most probably due some resonance effect induced by the laser excitation wavelength used. Raman scattering studies of WSe2 have generated much controversy with regards mode assignment and the shifts at with spectral peaks appear while there are no reports from Brillouin scattering studies of this material. Our Raman experiment shows that the Raman active E2g(1) 2g and A1g modes in WSe2 initially thought to be degenerate are not degenerate. This was verified by collecting spectra at different polarization configurations. One of the polarization configurations showed two closely separated peaks, enabling us to identify the constituent modes from the originally near-degenerate mode in the unpolarized spectrum. The velocity of the Rayleigh surface wave was extracted from the Brillouin spectra collected at different angles of incidence ranging from 35 to 80 degrees in a Brillouin light scattering experiment. The value of the velocity compares well with those previously reported for related materials. This work reports new results on the vibrational properties of Bi2Se3, Bi2Te3, Sb2Te3 and WSe2. Our results also resolves the inconsistencies reported in previous studies on the vibrational properties of these materials.
Author: Michael Scott Wolf Publisher: ISBN: Category : Antimony compounds Languages : en Pages : 58
Book Description
Topological insulators are currently a main focus of condensed matter research. They have a unique property in which the bulk of the material acts as an insulator, while the surface states display metallic behavior. Using infrared, optical and magneto-optical spectroscopy, we have studied 3D topological insulators Bi2Se3, Bi2Te3, Sb2Te3 to understand their optical properties. The measurements were carried out using a Fourier Transform Infrared Spectrometer (FTIR) and an ultraviolet-visible spectrometer at varying temperatures ranging from 5 Kelvin to 300 Kelvin and at varying magnetic fields up to 18 Tesla. We use the Drude-Lorentz model to replicate the experimental data of the samples allowing to gain an understanding of the physical phenomena happening in the infrared, visible and ultraviolet regions of radiation. This understanding gives us insight on the optical properties of the materials such as charge dynamics. Results show that the temperature and magnetic field have an effect on the charge carriers especially near the plasma frequency.
Author: Jiajun Zhu Publisher: diplom.de ISBN: 3960676603 Category : Science Languages : en Pages : 88
Book Description
Topological insulator is one of the hottest research topics in solid state physics. This is the first book to describe the vibrational spectroscopies and electrical transport of topological insulator Bi2Se3, one of the most exciting areas of research in condensed matter physics. In particular, attempts have been made to summarize and develop the various theories and new experimental techniques developed over years from the studies of Raman scattering, infrared spectroscopy and electrical transport of topological insulator Bi2Se3. It is intended for material and physics researchers and graduate students doing research in the field of optical and electrical properties of topological insulators, providing them the physical understanding and mathematical tools needed to engage research in this quickly growing field. Some key topics in the emerging field of topological insulators are introduced.
Author: Pan P. Adhikari Publisher: ISBN: Category : Condensed matter Languages : en Pages : 51
Book Description
Topological insulators are new states of quantum matter having their bulk as insulator but strange conducting properties present at their boundaries: edges (2D) and surfaces (3D). This is a blossoming research topic in condensed matter physics at the present time. They are thought to provide an excellent method for the realization of fault-tolerant quantum computing. We studied the optical properties and inter-band transitions of 3D topological insulators Bi2Se3, Bi2Te3, and Sb2Te3 by measuring the reflectivity using a UV-Visible spectrophotometer. In this work, we use the Drude-Lorentz model to fit the experimental data in the infrared, visible and ultraviolet regions of radiation (30-50,000 cm−1) and compare the reflectivity and optical conductivity for the three samples. Our results show that, in all three materials there are inter-band transitions: one major transition in Bi2Se3 and Sb2Te3, and two in Bi2Te3. These inter-band transitions cause relatively higher reflectivity R(w) values (-̃50%) in the visible region. Our results might be useful in the practical applications of topological insulators especially in laser applications.
Author: Publisher: Elsevier ISBN: 0444633189 Category : Science Languages : en Pages : 349
Book Description
Topological Insulators, volume six in the Contemporary Concepts of Condensed Matter Series, describes the recent revolution in condensed matter physics that occurred in our understanding of crystalline solids. The book chronicles the work done worldwide that led to these discoveries and provides the reader with a comprehensive overview of the field. Starting in 2004, theorists began to explore the effect of topology on the physics of band insulators, a field previously considered well understood. However, the inclusion of topology brings key new elements into this old field. Whereas it was thought that all band insulators are essentially equivalent, the new theory predicts two distinct classes of band insulators in two spatial dimensions and 16 classes in three dimensions. These "topological" insulators exhibit a host of unusual physical properties, including topologically protected gapless surface states and exotic electromagnetic response, previously thought impossible in such systems. Within a short time, this new state of quantum matter, topological insulators, has been discovered experimentally both in 2D thin film structures and in 3D crystals and alloys. It appears that topological insulators are quite common in nature, and there are dozens of confirmed substances that exhibit this behavior. Theoretical and experimental studies of these materials are ongoing with the goal of attaining the fundamental understanding and exploiting them in future practical applications. - Usable as a textbook for graduate students and as a reference resource for professionals - Includes the most recent discoveries and visions for future technological applications - All authors are prominent in the field
Author: Mikhail I. Dyakonov Publisher: Springer ISBN: 3319654365 Category : Technology & Engineering Languages : en Pages : 546
Book Description
This book offers an extensive introduction to the extremely rich and intriguing field of spin-related phenomena in semiconductors. In this second edition, all chapters have been updated to include the latest experimental and theoretical research. Furthermore, it covers the entire field: bulk semiconductors, two-dimensional semiconductor structures, quantum dots, optical and electric effects, spin-related effects, electron-nuclei spin interactions, Spin Hall effect, spin torques, etc. Thanks to its self-contained style, the book is ideally suited for graduate students and researchers new to the field.
Author: Sadao Adachi Publisher: World Scientific ISBN: 9814405949 Category : Science Languages : en Pages : 684
Book Description
Introduction -- Metal and semimetal elements -- Transition-metal carbides and nitrides -- Metallic silicides -- High-Tc superconductors.
Author: Jamal Najr Alnofiay
Author: Jamal Najr Alnofiay
Author: Kolawole Akintola
Author: Michael Scott Wolf
Author: Jiajun Zhu
Author: Pan P. Adhikari
Author: 
Author: Tobias Förster
Author: Markus Kotulla
Author: Mikhail I. Dyakonov
Author: Sadao Adachi