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Scientific databases offer remarkable potential for solving complex questions in materials science, such as global optimization of materials and designing unknown materials for novel properties. ThermoElectric materials eXplorer (TEXplorer) is a web-based platform designed to collect and share all types of thermoelectric materials data, including synthesis information, materials characterization, transport measurements, and electronic structures obtained from experiments and computations. TEXplorer also provides valuable tools, such as an easy upload and download system, retrieval, automatic post-processing calculations, visualization of datasets, and toolkits for predicting thermoelectric properties through machine learning models. Using the platform, we collected and managed the thermoelectric dataset of SnSe and Bi2Te3 with various doping/alloying elements in this study in order to investigate the complex relationship between doping/alloying elements and the thermoelectric properties of host materials. The web-based interactive data platform enables efficient management and utilization of experimental and computational datasets, supporting the acceleration of data-driven materials research and autonomous material synthesis.

The atomic and electronic structures of pristine, Mn- and Nb-doped grain boundaries in SrTiO3 are investigated by atomistic simulations and cluster calculations. The atomic structures of (310) symmetric tilt grain boundaries in SrTiO3 are determined by atomistic simulation using empirical potentials. The defect energies of Mn(Nb)-doped models are calculated and discussed in relation to the concentration profiles of Mn(Nb) in SrTiO3 grain boundaries. The local electronic structures near Mn(Nb)-doped grain boundaries in SrTiO3 are determined using embedded cluster calculations based on the density functional theory. The charge density of each system is calculated to elucidate the electronic structure of the grain boundary. The calculation results agree well with previous experimental observations of the atomic structures and grain boundary charges near the Mn(Nb)-doped grain boundary in SrTiO3.

Adsorption of NH3 and NO2 molecules on semiconducting single-walled carbon nanotubes is investigated using density functional theory. Both NH3 and NO2 molecules are found to bind to carbon nanotubes via physisorption. Electron charge transfer is found to be a major mechanism determining the conductivity change in carbon nanotubes upon exposure to NH3 and NO2 molecules. The calculated density of states is also considered to elucidate the differences in the NO2 and NH3 gas detection mechanism of carbon nanotubes.

We discuss appreciable differences between the results for the covalent reduction of the ordered moment in antiferromagnetic CuO2 planes obtained by various groups, including the present authors. We explain the differences as due to differences in definition, the definition that we used being closely based on experiment (magnetic neutron Bragg scattering), in contrast to the others. We also discuss the large difference between the zero‐point spin fluctuations as calculated by one of the groups and the well‐known result of spin wave theory.

We report air-stable n-type operations of the single-walled carbon nanotube field effect transistors (SWNT-FETs) fabricated with Gd electrodes. Unlike previously reported n-type SWNT-FETs, our devices maintained their n-type operation characteristics in ambient atmosphere for more than two months. The shallow Gd films with a thickness below 20 nm are corroded by environmental oxygen, whereas the well-contacted Gd-SWNT interfaces underneath the thick Gd layers are protected from contaminations by air molecules. Theoretical studies based on the first-principles electronic structure calculations confirm that Gd layers have an excellent binding affinity to the SWNTs.

The authors report the construction of carbon nanotube Schottky diodes by covering a selectively exposed area of the electrode with self-assembling molecules. Two self-assembling molecules with different polarities, 2-aminoethanethiol and 3-mercaptopropionic acid, were used to modify the Fermi level lineup at the selected contact. The devices showed p-type behavior with symmetric I-V showing clear rectifying behavior after treatment of one contact with 2-aminoethanethiol. Their experiment, in conjunction with the results of ab initio electronic structure calculations, suggests that the diode action stems from the asymmetric Fermi level lineup between the bare and engineered contacts.

We investigated the effect of humidity on the electrical transport properties of single-walled carbon nanotube field effect transistors (SWNT-FETs). Water molecules are found to behave as electron donors to the nanotube: Current through the p-type carbon nanotube device is found to decrease under a modest humidity, and starts to increase as the humidity increases over 65%, which is believed to be due to the opening of electron channels. Through first principles calculations based on the density functional theory, we found that water molecules can donate electrons to the carbon nanotube. Moreover, a hydrogen-bonded water monolayer will be formed around the nanotube at fully covered conditions. We suggest that this result could provide a systematic understanding of the humidity effect on SWNT-FETs, which has been believed to be essential in the development of nanotube-based sensors.