Fe-doping induced superconductivity in charge-density-wave system 1T-TaS2

We report the interplay between charge-density-wave (CDW) and superconductivity of 1$T$-Fe$_{x}$Ta$_{1-x}$S$_{2}$ ($0\leq x \leq 0.05$) single crystals. The CDW order is gradually suppressed by Fe-doping, accompanied by the disappearance of pseudogap/Mott-gap as shown by the density functional theory (DFT) calculations. The superconducting state develops at low temperatures within the CDW state for the samples with the moderate doping levels. The superconductivity strongly depends on $x$ within a narrow range, and the maximum superconducting transition temperature is 2.8 K as $x=0.02$. We propose that the induced superconductivity and CDW phases are separated in real space. For high doping level ($x>0.04$), the Anderson localization (AL) state appears, resulting in a large increase of resistivity. We present a complete electronic phase diagram of 1$T$-Fe$_{x}$Ta$_{1-x}$S$_{2}$ system that shows a dome-like $T_{c}(x)$

Hot electrons in low-dimensional phonon systems

A simple bulk model of electron-phonon coupling in metals has been surprisingly successful in explaining experiments on metal films that actually involve surface- or other low-dimensional phonons. However, by an exact application of this standard model to a semi-infinite substrate with a free surface, making use of the actual vibrational modes of the substrate, we show that such agreement is fortuitous, and that the model actually predicts a low-temperature crossover from the familiar T^5 temperature dependence to a stronger T^6 log T scaling. Comparison with existing experiments suggests a widespread breakdown of the standard model of electron-phonon thermalization in metals

Development and energy evaluation of phase change material composite for building energy-saving

SUMMARY Phase change materials (PCMs) contributed to building energy‐saving and thermal comfort through increasing the thermal capacity of building envelopes. In this study, a phase change material composite was developed by using the PCMs mixture of capric acid (CA) and lauric acid (LA) as the primary phase change energy storage agent and using the solid waste fly ash as a carrier material. The results showed that for Guangdong, the ideal PCMs mixture should have a transition temperature of 25.5oC, which could be obtained by using a mass ratio of CA/LA of 4:6. Then, experiment results also indicate that the optimum adsorption ratio of 2:1 (FA/PCMs) was detected for the synthesis of this FA/PCMs composite, which has the latent heat of 45.38 J/g and exists excellent thermal reliability. Moreover, simulation results by using EnergyPlus show that the proposed composite has a good building energy‐saving effect