scholarly journals High-harmonic spectra of hexagonal nanoribbons from real-space time-dependent Schrödinger calculations

2021 ◽  
Author(s):  
Helena Drüeke ◽  
Dieter Bauer
Keyword(s):  
Boron Nitride ◽  
Temporal Resolution ◽  
Electronic Structures ◽  
Hexagonal Boron Nitride ◽  
Condensed Matter ◽  
High Harmonic ◽  
Real Space ◽  
Time Dependent ◽  
Promising Candidate ◽  
All Optical

AbstractHigh-harmonic spectroscopy is a promising candidate for imaging electronic structures and dynamics in condensed matter by all-optical means and with unprecedented temporal resolution. We investigate harmonic spectra from finite, hexagonal nanoribbons, such as graphene and hexagonal boron nitride, in armchair and zig-zag configuration. The symmetry of the system explains the existence and intensity of the emitted harmonics.

scholarly journals Four-dimensional vibrational spectroscopy for nanoscale mapping of phonon dispersion in BN nanotubes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ruishi Qi ◽  
Ning Li ◽  
Jinlong Du ◽  
Ruochen Shi ◽  
Yang Huang ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Energy Loss ◽  
Phonon Dispersion ◽  
Hexagonal Boron Nitride ◽  
Real Space ◽  
Boron Nitride Nanotubes ◽  
Detection Sensitivity ◽  
Optical Modes ◽  
Optical And Mechanical Properties ◽  
Energy And Momentum

AbstractDirectly mapping local phonon dispersion in individual nanostructures can advance our understanding of their thermal, optical, and mechanical properties. However, this requires high detection sensitivity and combined spatial, energy and momentum resolutions, thus has been elusive. Here, we demonstrate a four-dimensional electron energy loss spectroscopy technique, and present position-dependent phonon dispersion measurements in individual boron nitride nanotubes. By scanning the electron beam in real space while monitoring both the energy loss and the momentum transfer, we are able to reveal position- and momentum-dependent lattice vibrations at nanometer scale. Our measurements show that the phonon dispersion of multi-walled nanotubes is locally close to hexagonal-boron nitride crystals. Interestingly, acoustic phonons are sensitive to defect scattering, while optical modes are insensitive to small voids. This work not only provides insights into vibrational properties of boron nitride nanotubes, but also demonstrates potential of the developed technique in nanoscale phonon dispersion measurements.

scholarly journals Time dependent decomposition of ammonia borane for the controlled production of 2D hexagonal boron nitride

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Vitaliy Babenko ◽  
George Lane ◽  
Antal A. Koos ◽  
Adrian T. Murdock ◽  
Karwei So ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Ammonia Borane ◽  
Time Dependent

REAL-TIME APPROACH TO TIME-DEPENDENT DENSITY-FUNCTIONAL THEORY IN THE LINEAR AND NONLINEAR REGIME

2009 ◽  
Vol 08 (04) ◽  
pp. 561-574 ◽  
Author(s):  
MICHAEL MUNDT
Keyword(s):  
Density Functional Theory ◽  
Real Time ◽  
Density Functional ◽  
High Harmonic ◽  
External Perturbation ◽  
Real Space ◽  
Time Dependent ◽  
Functional Theory ◽  
Linear And Nonlinear ◽  
Dependent Density

The linear and nonlinear response of Si 4 and Na 4 to an external perturbation is investigated in the framework of time-dependent density-functional theory. The time-dependent Kohn–Sham equations, which are the central equations in this approach, are solved in real space and real time. A parallelized implementation to solve these nonlinear, one-particle Schrödinger equations is presented. In contrast to Na 4, Si 4 shows high-harmonic generation far beyond the cut-off predicted by the quasiclassical model and predictions for extended systems.

scholarly journals Recent Progress in the Study of Thermal Properties and Tribological Behaviors of Hexagonal Boron Nitride-Reinforced Composites

2020 ◽  
Vol 4 (3) ◽  
pp. 116
Author(s):  
Maryam Khalaj ◽  
Sanaz Zarabi Golkhatmi ◽  
Sayed Ali Ahmad Alem ◽  
Kahila Baghchesaraee ◽  
Mahdi Hasanzadeh Azar ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Boron Nitride ◽  
Recent Progress ◽  
Phonon Scattering ◽  
Hexagonal Boron Nitride ◽  
High Thermal Conductivity ◽  
Promising Candidate ◽  
Reinforced Composite ◽  
Low Thermal Expansion ◽  
Wide Range

Ever-increasing significance of composite materials with high thermal conductivity, low thermal expansion coefficient and high optical bandgap over the last decade, have proved their indispensable roles in a wide range of applications. Hexagonal boron nitride (h-BN), a layered material having a high thermal conductivity along the planes and the band gap of 5.9 eV, has always been a promising candidate to provide superior heat transfer with minimal phonon scattering through the system. Hence, extensive researches have been devoted to improving the thermal conductivity of different matrices by using h-BN fillers. Apart from that, lubrication property of h-BN has also been extensively researched, demonstrating the effectivity of this layered structure in reduction of friction coefficient, increasing wear resistance and cost-effectivity of the process. Herein, an in-depth discussion of thermal and tribological properties of the reinforced composite by h-BN will be provided, focusing on the recent progress and future trends.

scholarly journals Publisher Correction: Time dependent decomposition of ammonia borane for the controlled production of 2D hexagonal boron nitride

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Vitaliy Babenko ◽  
George Lane ◽  
Antal A. Koos ◽  
Adrian T. Murdock ◽  
Karwei So ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Ammonia Borane ◽  
Time Dependent

Polarisation effects in hexagonal boron nitride near-edge structure: A real-space multiple scattering approach

2000 ◽  
Vol 49 (3) ◽  
pp. 343-349 ◽  
Author(s):  
M Jaouen ◽  
G Hug ◽  
B Ravel ◽  
A. L Ankudinov ◽  
J. J Rehr
Keyword(s):  
Boron Nitride ◽  
Multiple Scattering ◽  
Hexagonal Boron Nitride ◽  
Real Space ◽  
Edge Structure

scholarly journals Ultrafast high-harmonic nanoscopy of magnetization dynamics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sergey Zayko ◽  
Ofer Kfir ◽  
Michael Heigl ◽  
Michael Lohmann ◽  
Murat Sivis ◽  
...  
Keyword(s):  
Temporal Resolution ◽  
Optical Switching ◽  
Temporal Dynamics ◽  
Spatial Scales ◽  
High Harmonic ◽  
Real Space ◽  
Local Magnetization ◽  
Magnetization Dynamics ◽  
Wide Range ◽  
Spatio Temporal

AbstractLight-induced magnetization changes, such as all-optical switching, skyrmion nucleation, and intersite spin transfer, unfold on temporal and spatial scales down to femtoseconds and nanometers, respectively. Pump-probe spectroscopy and diffraction studies indicate that spatio-temporal dynamics may drastically affect the non-equilibrium magnetic evolution. Yet, direct real-space magnetic imaging on the relevant timescales has remained challenging. Here, we demonstrate ultrafast high-harmonic nanoscopy employing circularly polarized high-harmonic radiation for real-space imaging of femtosecond magnetization dynamics. We map quenched magnetic domains and localized spin structures in Co/Pd multilayers with a sub-wavelength spatial resolution down to 16 nm, and strobosocopically trace the local magnetization dynamics with 40 fs temporal resolution. Our compact experimental setup demonstrates the highest spatio-temporal resolution of magneto-optical imaging to date. Facilitating ultrafast imaging with high sensitivity to chiral and linear dichroism, we envisage a wide range of applications spanning magnetism, phase transitions, and carrier dynamics.

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