相关论文: Vibrational Properties of the Bi2Se3 Orthorhombic …
Bismuth selenide, a benchmark topological insulator, grows in a trigonal structure at ambient conditions and exhibits a number of enticing properties related to the formation of Dirac surface states. Besides this polytype, a metastable…
New boron-rich sulfide B6S and selenide B6Se have been discovered from high pressure - high temperature synthesis combined with ab initio evolutionary crystal structure prediction, and studied by synchrotron X-ray diffraction and Raman…
A new type of two-dimensional layered semiconductor with weak electrostatic but not van der Waals interlayer interactions, Bi2O2Se, has been recently synthesized, which shown excellent air stability and ultrahigh carrier mobility. Herein,…
High-pressure phase of boron oxide, orthorhombic \b{eta}-B2O3, has been studied in situ by synchrotron X-ray diffraction to 22 GPa and Raman scattering to 46 GPa at room temperature. The bulk modulus of \b{eta}-B2O3 has been found to be…
The hybrid halide perovskite CH3NH3PbI3 exhibits a complex structural behaviour, with successive transitions between orthorhombic, tetragonal and cubic polymorphs at ca. 165 K and 327 K. Herein we report first-principles lattice dynamics…
The tetradymite compound BiSbTeSe$_2$, is one of the most bulk-insulating three-dimensional topological insulators, which makes it important in the topological insulator research. It is a member of the solid-solution system…
The vibrational properties of ErTe$_3$ were investigated using Raman spectroscopy and analyzed on the basis of peculiarities of the RTe$_3$ crystal structure. Four Raman active modes for the undistorted structure, predicted by factor-group…
High quality single crystals of Bi2Se3 were grown using a modified Bridgman technique, the detailed study were carried out using Raman spectroscopy and characterized by Laue diffraction and high resolution transmission electron microscopy.…
Single crystals of the methylammonium (MA) lead halides MAPbI3, MAPbBr3, and MAPbCl3 have been investigated using infrared spectroscopy with the aim of analyzing structural and dynamical aspects of processes that enable the ordering of the…
On the basis of density functional theory electronic band structure calculations using the augmented spherical wave method, the electronic and magnetic properties of the orthorhombic and tetragonal phases of Ca3Mn2O7 were investigated and…
The ternary chalcogenide Bi2Rh3Se2 was found to be a charge density wave (CDW) superconductor with a 2*2 periodicity. The key questions regarding the underlying mechanism of CDW state and its interplay with lattice and electronic properties…
We report a theoretical study of Sb2S3, Sb2Se3 and Bi2S3 sesquichalcogenides at hydrostatic pressures up to 60 GPa. We explore the possibility that the R-3m, C2/m, C2/c and Im-3m phases observed in sesquichalcogenides with heavier cations,…
We report crystal growth and Raman spectroscopy characterization of pure and mixed bulk topological insulators. The series comprises of both binary and ternary tetradymite topological insulators. We analyzed in detail the Raman peaks of…
We report a systematic investigation of orthorhombic perovskite-type RCrO3 powder samples by Raman scattering for nine different rare earth R3+ cations (R = Y, La, Pr, Sm, Gd, Dy, Ho, Yb, Lu). The room-temperature Raman spectra and the…
Inelastic light scattering spectra of Bi_2Se_3 and Sb_2Te_3 single crystals have been measured over the temperature range from 5 K to 300 K. The temperature dependence of dominant A^{2}_{1g} phonons shows similar behavior in both materials.…
The antimony-based chalcogenide Sb2Se3 is a rapidly emerging material for photonic phase change applications owing to its ultra-low optical losses at telecommunication wavelengths in both crystalline and amorphous phases. Here, we…
We present a rationalization of the Raman spectra of orthorhombic and rhombohedral, stoichiometric and doped, manganese perovskites. In particular we study RMnO3 (R= La, Pr, Nd, Tb, Ho, Er, Y and Ca) and the different phases of Ca or Sr…
Structural changes in REMnO3 (RE= Y, Ho, Lu) under high pressure were examined by synchrotron x-ray diffraction methods at room temperature. Compression occurs more readily in the ab plane than along the c-axis. Under hydrostatic pressure…
Raman micro-spectroscopy is well suited for studying a variety of properties and has been applied to wide- ranging areas. Combined with tuneable temperature, Raman spectra can offer even more insights into the properties of materials.…
A first-principles study of the vibrational modes of PbTiO_3 in the ferroelectric tetragonal phase has been performed at all the main symmetry points of the Brillouin zone (BZ). The calculations use the local-density approximation and…