scholarly journals Operator-based derivation of phonon modes and characterization of correlations for trapped ions at zero and finite temperature

2016 ◽  
Vol 94 (21) ◽  
Author(s):  
U. Bissbort ◽  
W. Hofstetter ◽  
D. Poletti
Keyword(s):  
Finite Temperature ◽  
Trapped Ions ◽  
Phonon Modes

Characterization of ZnSe Nanoparticles Prepared Using Ultrasonic Radiation Method

1998 ◽  
Vol 536 ◽  
Author(s):  
Jianfeng Xu ◽  
Wei Ji ◽  
Sing-Hai Tang ◽  
Wei Huang
Keyword(s):  
Xps Analysis ◽  
Phonon Modes ◽  
Znse Nanoparticles ◽  
Raman Scattering Spectroscopy ◽  
Ultrasonic Radiation ◽  
Radiation Method ◽  
Zinc Blende ◽  
Average Size ◽  
Zinc Blende Structure

AbstractZnSe nanoparticles with an average size of 15 nm were prepared using the ultrasonic radiation method. The characterization was carried out by means of XRD, TEM, XPS and Raman scattering spectroscopy. The experimental results indicate that the as-prepared powders are composed of ZnSe with zinc-blende structure. The high purity of ZnSe particles was confirmed by XPS analysis. In the Raman spectra, TO and LO phonon modes were observed at 205 and 257 cm−1 in the ZnSe nanoparticles.

scholarly journals Investigation of Structural, Electrical and Vibrational Properties of Bi1.98A0.02Fe4O9 (A= Ba, Ce) Multiferroic Ceramics

2020 ◽  
Author(s):  
Poorva Sharma ◽  
Ashwini Kumar
Keyword(s):  
Ionic Conduction ◽  
Sol Gel ◽  
Low Frequency ◽  
X Ray Diffraction ◽  
Phonon Modes ◽  
Raman Scattering Spectroscopy ◽  
Practical Applications ◽  
Constant E ◽  
Size And Morphology

Abstract In this paper, we report the synthesis, phase formation and basic characterization of polycrystalline Bi2Fe4O9, Bi1.98Ba0.02Fe4O9, and Bi1.98Ce0.02Fe4O9 sample prepared through sol-gel route. Crystal structure of the as prepared samples have been characterized by X-ray diffraction and Raman scattering spectroscopy. All the obtained XRD peaks could be indexed to orthorhombic Pbam structure and revealed the formation of Bi2Fe4O9. Raman spectrum identifies Ag, B2g and B3g active optical phonon modes. The size and morphology of the nanoparticles have been analyzed using scanning electron microscopy (SEM). Dielectric constant (e') decreases with increase in frequency and it is constant at higher frequencies region and it can be explained on the basis of ionic conduction phenomenon in the low frequency region. The value of e' for all Bi2Fe4O9 based S1, S2, S3 and S4 samples are about 37, 75, 40 and 393, respectively at frequency 10 Hz. The observed properties signify that these materials are very useful in advanced technological and practical applications.

scholarly journals Thermometry in a Multipole Ion Trap

2020 ◽  
Vol 10 (15) ◽  
pp. 5264
Author(s):  
Markus Nötzold ◽  
Saba Zia Hassan ◽  
Jonas Tauch ◽  
Eric Endres ◽  
Roland Wester ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Md Simulation ◽  
Ion Trap ◽  
Linear Mapping ◽  
Trapped Ions ◽  
Translational Energy ◽  
Buffer Gas ◽  
The Finite Element Method ◽  
Potential Landscape

We present a characterization of the ions’ translational energy distribution in a multipole ion trap. A linear mapping between the energy distribution of the trapped ions onto the ions’ time-of-flight (TOF) to a detector is demonstrated. For low ion temperatures, a deviation from linearity is observed and can be attributed to the emergence of multiple potential minima. The potential landscape of the trapped ions is modeled via the finite element method, also accounting for subtleties such as surface-charge accumulation. We demonstrate the validity of our thermometry method by simulating the energy distribution of the ion ensemble thermalized with buffer gas using a Molecular Dynamics (MD) simulation. A comparison between the energy distribution of trapped ions in different multipole trap configurations—i.e., with hyperbolic rods, cylindrical rods, and cylindrical wires—is provided. With these findings, one can map the temperature of the trapped ions down to the Kelvin regime using their TOF distributions. This enables future studies on sympathetic cooling and chemical reactions involving ions in multipole traps.

scholarly journals Raman characterization of the optical phonons in AlxGa1−xN layers grown by MBE and MOCVD

1997 ◽  
Vol 2 ◽  
Author(s):  
A. Cros ◽  
H. Angerer ◽  
R. Handschuh ◽  
O. Ambacher ◽  
M. Stutzmann
Keyword(s):  
Phonon Mode ◽  
Aluminum Content ◽  
Composition Range ◽  
Theoretical Calculations ◽  
Phonon Modes ◽  
Sapphire Substrates ◽  
Mode Behavior ◽  
Raman Characterization

We present the results of Raman measurements performed on AlxGa1−xN layers grown by MBE and MOCVD. The films were deposited on (0001) c-sapphire substrates, and the aluminum content covered the whole composition range for x from 0 (GaN) to 1 (AlN). It is shown that the energies of both A1(TO) and A1(LO) phonon modes smoothly increase with increasing x, indicating a one-mode behavior. The E2 phonon mode, however, presents a different behavior. Its energy increases very slowly with aluminum content and, for x≈0.4, a new phonon mode shows up which is shifted to higher energies by 50 cm−1. This new line leads to the E2 AlN mode for increasing aluminum content. The linewidths and intensities of these modes strongly depend on composition. These results are compared with recent theoretical calculations. Finally, the Raman selection rules in the MBE and MOCVD samples are compared and conclusions about the quality of the layers are drawn.

scholarly journals Phonon-number-resolving detection of multiple local phonon modes in trapped ions

2019 ◽  
Vol 100 (6) ◽  
Author(s):  
Ryutaro Ohira ◽  
Takashi Mukaiyama ◽  
Kenji Toyoda
Keyword(s):  
Trapped Ions ◽  
Phonon Modes ◽  
Phonon Number

scholarly journals GAUGE DEPENDENCE AMBIGUITY AND CHEMICAL POTENTIAL IN THERMAL U(1) THEORY

2007 ◽  
Vol 22 (36) ◽  
pp. 2763-2773
Author(s):  
M. LOEWE ◽  
S. MENDIZABAL ◽  
R. A. SANTOS
Keyword(s):  
Phase Transition ◽  
Mass Spectrum ◽  
Effective Potential ◽  
Finite Temperature ◽  
Chemical Potential ◽  
Gauge Dependence ◽  
Dependence Problem ◽  
Gauge Fixing ◽  
The One

In this paper we explore the dependence on the gauge-fixing condition of several quantities in the U(1) Higgs model at finite temperature and chemical potential. We compute the effective potential at the one-loop level, using a gauge-fixing condition that depends on μ and which allows to decouple the contributions of the different fields in the model. In this way we get the mass spectrum and the characterization of the phase transition, pointing out in each case how these quantities depend on the gauge-fixing parameter ξ. When μ vanishes, we agree with previous results if ξ=0. The gauge dependence problem is also analyzed from the perspective of the Nielsen identities.

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