Pressure-induced phase transition, metallization and superconductivity in ZrS2

2018 ◽  
Vol 20 (36) ◽  
pp. 23656-23663 ◽  
Author(s):  
Hang Zhai ◽  
Zhen Qin ◽  
Dan Sun ◽  
Jianyun Wang ◽  
Chang Liu ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Phonon Coupling ◽  
Band Structures ◽  
Electronic Band ◽  
Electron Phonon Coupling ◽  
Electronic Band Structures ◽  
Stable Structures

The high-pressure thermodynamically stable structures of ZrS2 have been extensively identified using an effective CALYPSO algorithm. Our theoretical electronic band structures and electron–phonon coupling unravel the occurrence of pressure-induced metallization and superconductivity in ZrS2.

Study of the phase transition properties and electronic band structures of VO2 thin films grown on different substrates

2018 ◽  
Vol 6 (2) ◽  
pp. 026409
Author(s):  
Yunfeng Guo ◽  
Yuzhi Zhang ◽  
Liangmiao Zhang ◽  
Xinrui Lv ◽  
Lingnan Wu ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Band Structures ◽  
Electronic Band ◽  
Vo2 Thin Films ◽  
Electronic Band Structures

Tuning the electronic and vibrational properties of Sn2P2Se6and Pb2P2S6crystals and their metallization under high pressure

2017 ◽  
Vol 46 (13) ◽  
pp. 4245-4258 ◽  
Author(s):  
Sergey V. Ovsyannikov ◽  
Natalia V. Morozova ◽  
Igor V. Korobeinikov ◽  
Vasyl Haborets ◽  
Ruslan Yevych ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Vibrational Properties ◽  
Band Structures ◽  
Electronic Band ◽  
Electronic Band Structures

Ferroelectric Sn2P2Se6and paraelectric Pb2P2S6demonstrate the remarkable responses of their electronic band structures to applied high pressures.

Electronic band structures of NdFe3(BO3)4 and NdGa3(BO3)4 crystals: ab initio calculations

2021 ◽  
Vol 575 (1) ◽  
pp. 11-17
Author(s):  
S. Krylova ◽  
I. Gudim ◽  
A. Aleksandrovsky ◽  
A. Vtyurin ◽  
A. Krylov
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Band Structures ◽  
Electronic Band ◽  
Electronic Band Structures

scholarly journals Direct observation of excitonic instability in Ta2NiSe5

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kwangrae Kim ◽  
Hoon Kim ◽  
Jonghwan Kim ◽  
Changil Kwon ◽  
Jun Sung Kim ◽  
...  
Keyword(s):  
Phase Transition ◽  
Direct Observation ◽  
Structural Phase ◽  
Temperature Phase ◽  
Phonon Coupling ◽  
Strong Electron ◽  
Weiss Temperature ◽  
Excitonic Insulator ◽  
Electron Phonon Coupling ◽  
Low Temperature Phase

AbstractCoulomb attraction between electrons and holes in a narrow-gap semiconductor or a semimetal is predicted to lead to an elusive phase of matter dubbed excitonic insulator. However, direct observation of such electronic instability remains extremely rare. Here, we report the observation of incipient divergence in the static excitonic susceptibility of the candidate material Ta2NiSe5 using Raman spectroscopy. Critical fluctuations of the excitonic order parameter give rise to quasi-elastic scattering of B2g symmetry, whose intensity grows inversely with temperature toward the Weiss temperature of TW ≈ 237 K, which is arrested by a structural phase transition driven by an acoustic phonon of the same symmetry at TC = 325 K. Concurrently, a B2g optical phonon becomes heavily damped to the extent that its trace is almost invisible around TC, which manifests a strong electron-phonon coupling that has obscured the identification of the low-temperature phase as an excitonic insulator for more than a decade. Our results unambiguously reveal the electronic origin of the phase transition.

scholarly journals Phase-selective active sites on ordered/disordered titanium dioxide enable exceptional photocatalytic ammonia synthesis

2021 ◽  
Author(s):  
Jinsun Lee ◽  
Xinghui Liu ◽  
Ashwani Kumar ◽  
Yosep Hwang ◽  
Eunji Lee ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Active Sites ◽  
Rational Design ◽  
Ammonia Synthesis ◽  
Reduction Reaction ◽  
Band Structures ◽  
Electronic Band ◽  
Defect Sites ◽  
Electronic Band Structures ◽  
Reaction Routes

This work highlights the importance of a rational design for more energetically suitable nitrogen reduction reaction routes and mechanisms by regulating the electronic band structures with phase-selective defect sites.

Molecular Vibrations in the Exciton Theory for Molecular Aggregates. II. Dimeric Systems

1961 ◽  
Vol 14 (3) ◽  
pp. 344 ◽  
Author(s):  
EG McRae
Keyword(s):  
Absorption Spectrum ◽  
Perturbation Theory ◽  
Fluorescence Spectra ◽  
Numerical Calculations ◽  
Molecular Vibrations ◽  
Molecular Aggregates ◽  
Absorption And Fluorescence Spectra ◽  
Band Structures ◽  
Electronic Band ◽  
Electronic Band Structures

The theory of Part I of this series (McRae 1961) is developed in detail for dimeric systems. The simplest possible theory of the exciton states for a system of two non-rigid molecules is obtained through the use of perturbation theory. The theory makes possible the prediction of electronic band structures in absorption and fluorescence spectra as functions of the theoretical Davydov splitting for two rigid molecules. Numerical calculations are made for a dimer of a typical dye, and the results are compared with the observed absorption spectrum of the 1,1'-diethyl-2,2'-pyridocyanine iodide dimer.

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