Heat transport in low-dimensional materials: A review and perspective

Heat transport is a key energetic process in materials and devices. The reduced sample size, low dimension of the problem and the rich spectrum of material imperfections introduce fruitful phenomena at nanoscale. In this review, we summarize recent progresses in the understanding of heat transport process in low-dimensional materials, with focus on the roles of defects, disorder, interfaces, and the quantum- mechanical effect. New physics uncovered from computational simulations, experimental studies, and predictable models will be reviewed, followed by a perspective on open challenges.

Interface enhanced superconductivity in monolayer FeSe films on MgO(001):charge transfer with atomic substitution

Interface enhanced superconductivity over 50 K has been discovered in monolayer Fe Se films grown on several TiO_2-terminated oxide substrates.Whether such phenomenon exists in other oxide substrates remains an extremely interesting topic.Here we report enhanced superconductivity with an onset transition temperature of 18 K in monolayer Fe Se on Mg O(001) substrate by transport measurement.Scanning transmission electron microscopy investigation on the interface structure indicates that Fe Se films grow epitaxially on Mg O(001) and that overlayer Fe atoms diffuse into the top two layers of Mg O and substitute Mg atoms.Our density functional theory calculations reveal that this substitution promotes the charge transfer from the Mg O substrate to the Fe Se films,an essential process that also occurs in monolayer Fe Se on TiO_2-terminated oxides and contributes to the enhanced superconductivity therein.Our finding suggests that superconductivity enhancement in monolayer Fe Se films on oxides substrates is rather general as long as charge transfer is allowed at the interface,thus pointing out an explicit direction for searching for new high temperature superconductivity by interface engineering.

Non-equilibrium thermodynamics analysis and its application in interfacial mass transfer

Interfacial transfer plays an important role in multi-phase chemical processes. However, it is difficult to describe the complex interfacial transport behavior by the traditional mass transfer model. In this paper, we describe an interfacial mass transfer model based on linear non-equilibrium thermodynamics for the analysis of the rate of interfacial transport. The interfacial transfer process rate J depends on the interface mass transfer coefficient K, interfacial area A and chemical potential gradient at the interface. Potassium compounds were selected as model systems. A model based on linear non-equilibrium thermo-dynamics was established in order to describe and predict the transport rate at the solid-solution interface. Together with accurate experimental kinetic data for potassium ions obtained using ion-selective electrodes, a general model which can be used to describe the dissolution rate was established and used to analyze ways of improving the process rate.