Creation and control of a two-dimensional electron liquid at the bare SrTiO3 surface

Many-body interactions in transition-metal oxides give rise to a wide range of functional properties, such as high-temperature superconductivity, colossal magnetoresistance, or multiferroicity. The seminal recent discovery of a two-dimensional electron gas (2DEG) at the interface of the insulating oxides LaAlO3 and SrTiO3 represents an important milestone towards exploiting such properties in all-oxide devices. This conducting interface shows a number of appealing properties, including a high electron mobility, superconductivity, and large magnetoresistance and can be patterned on the few-nanometer length scale. However, the microscopic origin of the interface 2DEG is poorly understood. Here, we show that a similar 2DEG, with an electron density as large as 8x10^13 cm^-2, can be formed at the bare SrTiO3 surface. Furthermore, we find that the 2DEG density can be controlled through exposure of the surface to intense ultraviolet (UV) light. Subsequent angle-resolved photoemission spectroscopy (ARPES) measurements reveal an unusual coexistence of a light quasiparticle mass and signatures of strong many-body interactions.Comment: 14 pages, 4 figures, supplementary information (see other files

Ultrafast charge transfer processes accompanying KLL Auger decay in aqueous KCl solution

X-ray photoelectron spectroscopy (XPS) and KLL Auger spectra of aqueous KCl solution were measured for the K$^+$ and Cl$^-$ edges. While the XPS spectra of potassium and chloride have similar structures, both exhibiting only weak satellite structures near the main line, the Auger spectra of these isoelectronic ions differ dramatically. A very strong satellite peak was found in the K$^+$ KLL Auger spectrum at the low kinetic energy side of the $^1$D state. Using equivalent core models and ab initio calculations this spectral structure was assigned to electron transfer processes from solvent water molecules to the solvated K$^+$ cation. Contrary to the potassium case, no extra peak was found in the KLL Auger spectrum of solvated Cl$^-$ indicating on a strong dependence of the underlying processes on ionic charge. The observed charge transfer processes are suggested to play an important role in charge redistribution following single and multiple core-hole creation in atomic and molecular systems placed into an environment

Interfacial behavior of resistive switching in ITO–PVK–Al WORM memory devices

10.1088/0022-3727/49/7/075104Journal of Physics D: Applied Physics497075104-07510

Electrostatic model of the energy-bending within organic semiconductors: experiment and simulation

10.1088/0953-8984/28/36/365002Journal of Physics: Condensed Matter2836365002-36500

Exécution adaptative par observation et analyse de comportements (application à des logiciels interactifs pour des enfants autistes)

Taking into account of the user's behaviour in interactive applications, including human users, appears evident to develop a fast decision-making model and adapted to the situation. It consists in extracting conclusions relating to user's behaviour and provides in a real time personalized way adequate activities, keeping in mind the expert's advice. Within this framework, we have contributed to solve the adaptive execution problem by observing and analysing of behaviour. The first part concerns behaviour analysis. We thus defined a formalism based on observation of user's behaviour. It concerns the observation carried out on the explicit and implicit actions of user. User's explicit actions are recorded with the help of: mouse, touch screen and keyboard. User's implicit actions concern the facial expressions. The second part is about execution control models that take into account users behaviours. We have defined a model based on the case-based reasoning that allows the generation of activities corresponding to the user's profile, his needs and behaviour. Our strategy of control consists in launching an episode of reasoning each time that a particular behaviour is detected.The application context relates to interactive software for autistic children. This application's framework represents the characteristic of a user-adapted and interactive implementation appropriate for each autistic child's behaviour. It constitutes a framework of application and the validation of our contribution.La prise en compte du comportement de l'utilisateur dans les applications interactives, qui incluent l'utilisateur humain, apparaît évidente pour la mise en œuvre d'un mécanisme de prise de décision rapide et adaptée à la situation. Il s'agit de définir un système capable de comprendre le comportement de l'utilisateur et d'y répondre, de manière personnalisée et en temps réel, par des activités adaptées en tenant compte des consignes du concepteur de l'application. Dans ce cadre, nous avons apporté notre contribution à la problématique de l'exécution adaptative par observation et analyse du comportement. La première partie de notre travail concerne l'étude des approches d'analyse de comportements. Nous avons défini un formalisme basé sur l'observation. Il s'agit d'observations effectuées sur les actions explicites (clavier, écran tactile, etc.) et implicites (concernant les expressions faciales) de l'utilisateur. La seconde partie concerne les modèles du contrôle d'exécution en tenant compte du comportement de l'utilisateur. Nous avons conçu un modèle fondé sur le raisonnement à partir de cas permettant la génération des activités répondant au profil de l'utilisateur, ses besoins et son comportement. Le principe de contrôle, que nous avons élaboré, consiste à déclencher un épisode de raisonnement à chaque fois qu'un comportement portant un intérêt particulier est détecté.Le contexte applicatif concerne des logiciels interactifs destinés à des enfants autistes. Ce contexte présente les caractéristiques d'une exécution adaptative et interactive adéquate au comportement de chaque enfant, ce qui constitue un cadre d'application et de validation de notre contribution.LA ROCHELLE-BU (173002101) / SudocSudocFranceF

Investigation into the Gaussian density of states widths of organic semiconductors

10.1088/0022-3727/49/32/325106Journal of Physics D: Applied Physics4932325106-32510

Energy level alignment of blended organic semiconductors and electrodes at the interface

10.1016/j.cap.2018.05.002CURRENT APPLIED PHYSICS189982-99