Effects of electron-phonon coupling on absorption spectrum: K edge of hexagonal boron nitride

2018 ◽  
Vol 98 (23) ◽  
Author(s):  
Ferenc Karsai ◽  
Moritz Humer ◽  
Espen Flage-Larsen ◽  
Peter Blaha ◽  
Georg Kresse
Keyword(s):  
Absorption Spectrum ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Phonon Coupling ◽  
Electron Phonon Coupling

scholarly journals Enhanced electron-phonon coupling in doubly aligned hexagonal boron nitride bilayer graphene heterostructure

2021 ◽  
Vol 103 (11) ◽  
Author(s):  
Manabendra Kuiri ◽  
Saurabh Kumar Srivastav ◽  
Sujay Ray ◽  
Kenji Watanabe ◽  
Takashi Taniguchi ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Bilayer Graphene ◽  
Phonon Coupling ◽  
Electron Phonon Coupling

scholarly journals Nonadiabatic superconductivity in a Li-intercalated hexagonal boron nitride bilayer

2020 ◽  
Vol 11 ◽  
pp. 1178-1189
Author(s):  
Kamila A Szewczyk ◽  
Izabela A Domagalska ◽  
Artur P Durajski ◽  
Radosław Szczęśniak
Keyword(s):  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Point Of View ◽  
Coupling Constant ◽  
Electron Phonon Interaction ◽  
Vertex Corrections ◽  
Electron Phonon Coupling ◽  
Nonadiabatic Effects ◽  
Debye Frequency ◽  
Very High

When considering a Li-intercalated hexagonal boron nitride bilayer (Li-hBN), the vertex corrections of electron–phonon interaction cannot be omitted. This is evidenced by the very high value of the ratio λωD/εF ≈ 0.46, where λ is the electron–phonon coupling constant, ωD is the Debye frequency, and εF represents the Fermi energy. Due to nonadiabatic effects, the phonon–induced superconducting state in Li-hBN is characterized by much lower values of the critical temperature (T LOVC C ∈ {19.1, 15.5, 11.8} K, for μ* ∈ {0.1, 0.14, 0.2}, respectively) than would result from calculations not taking this effect into account (T ME C∈ {31.9, 26.9, 21} K). From the technological point of view, the low value of T C limits the possible applications of Li-hBN. The calculations were carried out under the classic Migdal–Eliashberg formalism (ME) and the Eliashberg theory with lowest-order vertex corrections (LOVC). We show that the vertex corrections of higher order (λ3) lower the value of T LOVC C by a few percent.

Effect of strong phonon–phonon coupling on the temperature dependent structural stability and frequency shift of 2D hexagonal boron nitride

2016 ◽  
Vol 18 (4) ◽  
pp. 2672-2681 ◽  
Author(s):  
P. Anees ◽  
M. C. Valsakumar ◽  
B. K. Panigrahi
Keyword(s):  
Boron Nitride ◽  
Frequency Shift ◽  
Structural Stability ◽  
Hexagonal Boron Nitride ◽  
Phonon Coupling ◽  
Temperature Dependent ◽  
Stability Frequency

We report the effect of strong anharmonic phonon–phonon coupling on the temperature dependent structural stability, frequency shift and linewidth of 2D h-BN.

PHOTOINDUCED IR ABSORPTION IN AMnO3 AS A FUNCTION OF THE A SITE IONIC SPECIES

2000 ◽  
Vol 14 (29n31) ◽  
pp. 3590-3595 ◽  
Author(s):  
T. MERTELJ ◽  
M. HROVAT ◽  
D. KUSCER ◽  
D. MIHAILOVIC
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Ionic Species ◽  
Ir Absorption ◽  
Coupling Constant ◽  
Phonon Coupling ◽  
Photoinduced Absorption ◽  
Polaron Hopping ◽  
Electron Phonon Coupling ◽  
A Site

A comparison of photoinduced absorption spectra in AMnO 3 with A = La 3+, Nd 3+, Ca 2+ is presented. The spectra are analyzed in the framework of photon assisted polaron hopping. In contrast to LaMnO 3 and NdMnO 3 the photoinduced absorption spectrum of CaMnO 3 shows distinct contributions from photoexcited holes and electrons. Both contributions are identified, and our results imply that magnitude of electron-phonon coupling constant for electrons in Mn eg orbitals in CaMnO 3 is significantly smaller than in LaMnO 3.

scholarly journals Phonon transport at the interfaces of vertically stacked graphene and hexagonal boron nitride heterostructures

Nanoscale ◽  
2016 ◽  
Vol 8 (7) ◽  
pp. 4037-4046 ◽  
Author(s):  
Zhequan Yan ◽  
Liang Chen ◽  
Mina Yoon ◽  
Satish Kumar
Keyword(s):  
Boron Nitride ◽  
Physical Mechanism ◽  
Hexagonal Boron Nitride ◽  
Phonon Transport ◽  
Analysis Method ◽  
Phonon Coupling ◽  
Phonon Modes ◽  
Thermal Boundary Conductance

h-BN/graphene/h-BN sandwiched systems exhibit distinct stacking-dependent phonon transport features. We provide a new analysis method to understand the physical mechanism of phonon–phonon coupling and the phonon modes’ contributions to the thermal boundary conductance at SLG/h-BN interfaces.

scholarly journals Giant shift upon strain on the fluorescence spectrum of VNNB color centers in h-BN

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Song Li ◽  
Jyh-Pin Chou ◽  
Alice Hu ◽  
Martin B. Plenio ◽  
Péter Udvarhelyi ◽  
...  
Keyword(s):  
Color Center ◽  
Hexagonal Boron Nitride ◽  
Phonon Coupling ◽  
Strong Electron ◽  
Zero Phonon Line ◽  
Quantum Bit ◽  
Vacancy Pair ◽  
Electron Phonon Coupling ◽  
Pair Defect ◽  
Optical Activation

Abstract We study the effect of strain on the physical properties of the nitrogen antisite-vacancy pair in hexagonal boron nitride (h-BN), a color center that may be employed as a quantum bit in a two-dimensional material. With group theory and ab initio analysis we show that strong electron–phonon coupling plays a key role in the optical activation of this color center. We find a giant shift on the zero-phonon-line (ZPL) emission of the nitrogen antisite-vacancy pair defect upon applying strain that is typical of h-BN samples. Our results provide a plausible explanation for the experimental observation of quantum emitters with similar optical properties but widely scattered ZPL wavelengths and the experimentally observed dependence of the ZPL on the strain.

Marcus-Hush Theory Revealed by Electron Tunneling Through Hexagonal Boron Nitride

2019 ◽  
Author(s):  
Matěj Velický ◽  
Sheng Hu ◽  
Colin R. Woods ◽  
Peter S. Toth ◽  
Viktor Zólyomi ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Boron Nitride ◽  
Electron Tunneling ◽  
Hexagonal Boron Nitride ◽  
Large Body ◽  
Liquid Solution ◽  
Limiting Current ◽  
Electron Transfer Rate Constant ◽  
Electrochemical Parameters ◽  
Voltammetric Measurements

Marcus-Hush theory of electron transfer is one of the pillars of modern electrochemistry with a large body of supporting experimental evidence presented to date. However, some predictions, such as the electrochemical behavior at microdisk electrodes, remain unverified. Herein, we present a study of electron tunneling across a hexagonal boron nitride barrier between a graphite electrode and redox levels in a liquid solution. This was achieved by the fabrication of microdisk electrodes with a typical diameter of 5 µm. Analysis of voltammetric measurements, using two common redox mediators, yielded several electrochemical parameters, including the electron transfer rate constant, limiting current, and transfer coefficient. They show a significant departure from the Butler-Volmer behavior in a clear manifestation of the Marcus-Hush theory of electron transfer. In addition, our system provides a novel experimental platform, which could be applied to address a number of scientific problems such as identification of reaction mechanisms, surface modification, or long-range electron transfer.

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