scholarly journals Evidence of a coupled electron-phonon liquid in NbGe2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hung-Yu Yang ◽  
Xiaohan Yao ◽  
Vincent Plisson ◽  
Shirin Mozaffari ◽  
Jan P. Scheifers ◽  
...  

AbstractWhereas electron-phonon scattering relaxes the electron’s momentum in metals, a perpetual exchange of momentum between phonons and electrons may conserve total momentum and lead to a coupled electron-phonon liquid. Such a phase of matter could be a platform for observing electron hydrodynamics. Here we present evidence of an electron-phonon liquid in the transition metal ditetrelide, NbGe2, from three different experiments. First, quantum oscillations reveal an enhanced quasiparticle mass, which is unexpected in NbGe2 with weak electron-electron correlations, hence pointing at electron-phonon interactions. Second, resistivity measurements exhibit a discrepancy between the experimental data and standard Fermi liquid calculations. Third, Raman scattering shows anomalous temperature dependences of the phonon linewidths that fit an empirical model based on phonon-electron coupling. We discuss structural factors, such as chiral symmetry, short metallic bonds, and a low-symmetry coordination environment as potential design principles for materials with coupled electron-phonon liquid.

2016 ◽  
Vol 30 (17) ◽  
pp. 1650188 ◽  
Author(s):  
R. V. Vovk ◽  
G. Ya. Khadzhai ◽  
O. V. Dobrovolskiy ◽  
S. N. Kamchatna ◽  
A. Chroneos

The influence of a high hydrostatic pressure on the basal-plane electrical resistance along the twin boundaries in underdoped HoBa2Cu3O[Formula: see text] single crystals is investigated. An enhancement of the phase segregation caused by the high-pressure-induced redistribution of the labile oxygen has been revealed. The temperature dependences of the electrical resistance above [Formula: see text] can be approximated well within the framework of the model of [Formula: see text] electron–phonon scattering.


2014 ◽  
Vol 5 (3) ◽  
pp. 982-992 ◽  
Author(s):  
M AL-Jalali

Resistivity temperature – dependence and residual resistivity concentration-dependence in pure noble metals(Cu, Ag, Au) have been studied at low temperatures. Dominations of electron – dislocation and impurity, electron-electron, and electron-phonon scattering were analyzed, contribution of these mechanisms to resistivity were discussed, taking into consideration existing theoretical models and available experimental data, where some new results and ideas were investigated.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Junsoo Park ◽  
Maxwell Dylla ◽  
Yi Xia ◽  
Max Wood ◽  
G. Jeffrey Snyder ◽  
...  

AbstractBand convergence is considered a clear benefit to thermoelectric performance because it increases the charge carrier concentration for a given Fermi level, which typically enhances charge conductivity while preserving the Seebeck coefficient. However, this advantage hinges on the assumption that interband scattering of carriers is weak or insignificant. With first-principles treatment of electron-phonon scattering in the CaMg2Sb2-CaZn2Sb2 Zintl system and full Heusler Sr2SbAu, we demonstrate that the benefit of band convergence can be intrinsically negated by interband scattering depending on the manner in which bands converge. In the Zintl alloy, band convergence does not improve weighted mobility or the density-of-states effective mass. We trace the underlying reason to the fact that the bands converge at a one k-point, which induces strong interband scattering of both the deformation-potential and the polar-optical kinds. The case contrasts with band convergence at distant k-points (as in the full Heusler), which better preserves the single-band scattering behavior thereby successfully leading to improved performance. Therefore, we suggest that band convergence as thermoelectric design principle is best suited to cases in which it occurs at distant k-points.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shama ◽  
R. K. Gopal ◽  
Goutam Sheet ◽  
Yogesh Singh

AbstractPd$$_{3}$$ 3 Bi$$_{2}$$ 2 S$$_{2}$$ 2 (PBS) is a recently proposed topological semimetal candidate. However, evidence for topological surface states have not yet been revealed in transport measurements due to the large mobility of bulk carriers. We report the growth and magneto-transport studies of PBS thin films where the mobility of the bulk carriers is reduced by two orders of magnitude, revealing for the first time, contributions from the 2-dimensional (2D) topological surface states in the observation of the 2D weak anti-localization (WAL) effect in magnetic field and angle dependent conductivity measurements. The magnetotransport data is analysed within the 2D Hikami-Larkin-Nagaoka (HLN) theory. The analysis suggests that multiple conduction channels contribute to the transport. It is also found that the temperature dependence of the dephasing length can’t be explained only by electron-electron scattering and that electron-phonon scattering also contributes to the phase relaxation mechanism in PBS films.


2020 ◽  
Vol 102 (11) ◽  
Author(s):  
Ransell D'Souza ◽  
Jiang Cao ◽  
José D. Querales-Flores ◽  
Stephen Fahy ◽  
Ivana Savić

ACS Omega ◽  
2019 ◽  
Vol 4 (25) ◽  
pp. 21487-21493 ◽  
Author(s):  
Benoit Galvani ◽  
Daniel Suchet ◽  
Amaury Delamarre ◽  
Marc Bescond ◽  
Fabienne Velia Michelini ◽  
...  

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