scholarly journals Observation of second sound in graphite at temperatures above 100 K

Science ◽  
2019 ◽  
Vol 364 (6438) ◽  
pp. 375-379 ◽  
Author(s):  
S. Huberman ◽  
R. A. Duncan ◽  
K. Chen ◽  
B. Song ◽  
V. Chiloyan ◽  
...  
Keyword(s):  
Thermal Transport ◽  
Low Temperatures ◽  
Practical Importance ◽  
Layered Materials ◽  
Optical Measurements ◽  
Two Dimensional ◽  
Second Sound ◽  
Rare Occurrence ◽  
Time Resolved

Wavelike thermal transport in solids, referred to as second sound, is an exotic phenomenon previously limited to a handful of materials at low temperatures. The rare occurrence of this effect restricted its scientific and practical importance. We directly observed second sound in graphite at temperatures above 100 kelvins by using time-resolved optical measurements of thermal transport on the micrometer-length scale. Our experimental results are in qualitative agreement with ab initio calculations that predict wavelike phonon hydrodynamics. We believe that these results potentially indicate an important role of second sound in microscale transient heat transport in two-dimensional and layered materials in a wide temperature range.

Mechanical, thermal transport, electronic and photocatalytic properties of penta-PdPS, -PdPSe and -PdPTe monolayers explored by first-principles calculations

2021 ◽  
Author(s):  
Bohayra Mortazavi ◽  
Masoud Shahrokhi ◽  
Xiaoying Zhuang ◽  
Alexander V. Shapeev ◽  
Timon Rabczuk
Keyword(s):  
First Principles ◽  
Thermal Transport ◽  
2D Materials ◽  
Layered Materials ◽  
Photocatalytic Properties ◽  
Two Dimensional ◽  
First Principles Calculations

In the latest experimental advances in the field of two-dimensional (2D) materials, penta-PdPS and penta-PdPSe layered materials have been fabricated. In this work, we conduct first-principles calculations to explore the...

Optical Measurements of Correlated States of Two Dimensional Electrons in GaAs at Low Temperatures and High Magnetic Fields

1991 ◽  
Vol T39 ◽  
pp. 223-229 ◽  
Author(s):  
J F Ryan ◽  
R G Clark ◽  
R A Ford ◽  
C T Foxon ◽  
J J Harris ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Low Temperatures ◽  
Optical Measurements ◽  
High Magnetic Fields ◽  
Two Dimensional

Dislocation Core Properties in Bulk and Layered Materials

1988 ◽  
Vol 141 ◽  
Author(s):  
M.S. Duesbery ◽  
B. Grossmann ◽  
B. Joo
Keyword(s):  
Physical Properties ◽  
Dislocation Core ◽  
Layered Materials ◽  
Melting Transition ◽  
Surface Films ◽  
2D Systems ◽  
Major Contributor ◽  
Two Dimensional ◽  
Bulk Materials

AbstractThe dislocation core is now recognised as a major contributor to many physical properties in bulk materials, for example the plasticity of metals. Less well known is that the dislocation core can be similarly important in two-dimensional (2D) systems such as surface films. Core properties in bulk materials are reviewed briefly, with emphasis on the diversity of behavior and on unifying concepts. Dislocation cores in 2D matter are considered in more detail, with particular reference to the role of the dislocation core in the melting transition.

scholarly journals Phonon-assisted processes in the ultraviolet-transient optical response of graphene

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Dino Novko ◽  
Marko Kralj
Keyword(s):  
Dominant Role ◽  
Chemical Doping ◽  
Two Dimensional ◽  
Many Body ◽  
Time Resolved ◽  
Electron Phonon Interaction ◽  
Spectral Changes ◽  
Two Dimensional Materials ◽  
Many Body Interactions

AbstractMany recent experiments investigated potential and attractive means of modifying many-body interactions in two-dimensional materials through time-resolved spectroscopy techniques. However, the role of ultrafast phonon-assisted processes in two-dimensional systems is rarely discussed in depth. Here, we investigate the role of electron–phonon interaction in the transient optical absorption of graphene by means of first-principles methods. It is shown at equilibrium that the phonon-assisted transitions renormalize significantly the electronic structure. As a result, absorption peak around the Van-Hove singularity broadens and redshifts by ~100 meV. In addition, temperature increase and chemical doping are shown to notably enhance these phonon-assisted features. In the photoinduced transient response, we obtain spectral changes in close agreement with the experiments, and we associate them to the strong renormalization of occupied and unoccupied $$\pi$$π bands, which predominantly comes from the coupling with the zone-center $${E}_{2g}$$E2g optical phonon. Our estimation of the Coulomb interaction effects shows that the phonon-assisted processes can have a dominant role even in the subpicosecond regime.

Predicted low thermal conductivities in antimony films and the role of chemical functionalization

2016 ◽  
Vol 18 (43) ◽  
pp. 30061-30067 ◽  
Author(s):  
Tian Zhang ◽  
Yuan-Yuan Qi ◽  
Xiang-Rong Chen ◽  
Ling-Cang Cai
Keyword(s):  
Crystal Structure ◽  
Thermal Transport ◽  
Effective Means ◽  
Two Dimensional ◽  
Chemical Functionalization ◽  
Thermal Conductivities

Chemical functionalization is an effective means of tuning the electronic and crystal structure of a two-dimensional material, but very little is known regarding the correlation between thermal transport and chemical functionalization.

Single layer lead iodide: computational exploration of structural, electronic and optical properties, strain induced band modulation and the role of spin–orbital-coupling

Nanoscale ◽  
2015 ◽  
Vol 7 (37) ◽  
pp. 15168-15174 ◽  
Author(s):  
Mei Zhou ◽  
Wenhui Duan ◽  
Ying Chen ◽  
Aijun Du
Keyword(s):  
Optical Properties ◽  
Electronic Structures ◽  
Single Layer ◽  
Layered Materials ◽  
Two Dimensional ◽  
Lead Iodide ◽  
Spin Orbital ◽  
Computational Exploration ◽  
Spin Orbital Coupling

Graphitic like layered materials exhibit intriguing electronic structures and thus the search for new types of two-dimensional (2D) monolayer materials is of great interest for developing novel nano-devices.

The Role of the Initiator System in the Synthesis of Acidic Multifunctional Nanoparticles Designed for Molecular Imprinting of Proteins

2020 ◽  
Vol 65 (1) ◽  
pp. 28-41
Author(s):  
Marwa Aly Ahmed ◽  
Júlia Erdőssy ◽  
Viola Horváth
Keyword(s):  
Acrylic Acid ◽  
Binding Affinity ◽  
Molecular Imprinting ◽  
Low Temperatures ◽  
Ammonium Persulfate ◽  
Sodium Bisulfite ◽  
Multifunctional Nanoparticles ◽  
High Affinity ◽  
Initiator System

Multifunctional nanoparticles have been shown earlier to bind certain proteins with high affinity and the binding affinity could be enhanced by molecular imprinting of the target protein. In this work different initiator systems were used and compared during the synthesis of poly (N-isopropylacrylamide-co-acrylic acid-co-N-tert-butylacrylamide) nanoparticles with respect to their future applicability in molecular imprinting of lysozyme. The decomposition of ammonium persulfate initiator was initiated either thermally at 60 °C or by using redox activators, namely tetramethylethylenediamine or sodium bisulfite at low temperatures. Morphology differences in the resulting nanoparticles have been revealed using scanning electron microscopy and dynamic light scattering. During polymerization the conversion of each monomer was followed in time. Striking differences were demonstrated in the incorporation rate of acrylic acid between the tetramethylethylenediamine catalyzed initiation and the other systems. This led to a completely different nanoparticle microstructure the consequence of which was the distinctly lower lysozyme binding affinity. On the contrary, the use of sodium bisulfite activation resulted in similar nanoparticle structural homogeneity and protein binding affinity as the thermal initiation.

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