RESUMEN
Identifying the two-dimensional (2D) topological insulating (TI) state in new materials and its control are crucial aspects towards the development of voltage-controlled spintronic devices with low-power dissipation. Members of the 2D transition metal dichalcogenides have been recently predicted and experimentally reported as a new class of 2D TI materials, but in most cases edge conduction seems fragile and limited to the monolayer phase fabricated on specified substrates. Here, we realize the controlled patterning of the 1T^{'} phase embedded into the 2H phase of thin semiconducting molybdenum-disulfide by laser beam irradiation. Integer fractions of the quantum of resistance, the dependence on laser-irradiation conditions, magnetic field, and temperature, as well as the bulk gap observation by scanning tunneling spectroscopy and theoretical calculations indicate the presence of the quantum spin Hall phase in our patterned 1T^{'} phases.
RESUMEN
Realization of the quantum spin Hall effect in graphene devices has remained an outstanding challenge dating back to the inception of the field of topological insulators. Graphene's exceptionally weak spin-orbit coupling-stemming from carbon's low mass-poses the primary obstacle. We experimentally and theoretically study artificially enhanced spin-orbit coupling in graphene via random decoration with dilute Bi2Te3 nanoparticles. Multiterminal resistance measurements suggest the presence of helical edge states characteristic of a quantum spin Hall phase; the magnetic field and temperature dependence of the resistance peaks, x-ray photoelectron spectra, scanning tunneling spectroscopy, and first-principles calculations further support this scenario. These observations highlight a pathway to spintronics and quantum information applications in graphene-based quantum spin Hall platforms.
RESUMEN
Among atomically thin two-dimensional (2D) materials, molybdenum disulfide (MoS2) is attracting considerable attention because of its direct bandgap in the 2H-semiconducting phase. On the other hand, a 1T-metallic phase has been revealed, bringing complementary application. Recently, thanks to top-down fabrication using electron beam (EB) irradiation techniques, in-plane 1T-metal/2H-semiconductor lateral (Schottky) MoS2 junctions were demonstrated, opening a path toward the co-integration of active and passive two-dimensional devices. Here, we report the first transport measurements evidencing the formation of a MoS2 Schottky barrier (SB) junction with barrier height of 0.13-0.18 eV created at the interface between EB-irradiated (1T)/nonirradiated (2H) regions. Our experimental findings, supported by state-of-the-art simulation, reveal unique device fingerprint of SB-based field-effect transistors made from atom-thin 1T layers.
RESUMEN
Magneto-caloric effects (MCEs) measurement system in adiabatic condition is proposed to investigate the thermodynamic properties in pulsed magnetic fields up to 55 T. With taking the advantage of the fast field-sweep rate in pulsed field, adiabatic measurements of MCEs were carried out at various temperatures. To obtain the prompt response of the thermometer in the pulsed field, a thin film thermometer is grown directly on the sample surfaces. The validity of the present setup was demonstrated in the wide temperature range through the measurements on Gd at about room temperature and on Gd3Ga5O12 at low temperatures. The both results show reasonable agreement with the data reported earlier. By comparing the MCE data with the specific heat data, we could estimate the entropy as functions of magnetic field and temperature. The results demonstrate the possibility that our approach can trace the change in transition temperature caused by the external field.
RESUMEN
Three orthodontically treated cases with sounds of the temporomandibular joint are presented. Case 1: Eight months after [formula: see text] extraction, bilateral TMJ sounds were noticed. The patient had a history of pre-orthodontic TMJ sounds and locking. A disc recapturing splint was therefore set on the upper arch, then changed into a stabilization splint for 5 months. The TMJ sounds faded away and the active treatment was completed. Case 2: The patient had [formula: see text] missing teeth, severe deep bite, upper and lower spaced arches. She also had mild facial deformity and bilateral TMJ sounds. TMJ arthroscopy showed right side "Anterior disk displacement without reduction" and left side "Anterior disk displacement with reduction". Maxillary spaces were closed following standard splint therapy. Right side TMJ sound diminished considerably while left side sound faded away completely. Finally, prosthodontic treatment was performed. Case 3: The patient had mandibular right side shifting, upper and lower crowding and a right side TMJ sound. Initially, maxillary lateral expansion was performed using a Quad-helix appliance. Simultaneously a positioner-type splint was used on the lower arch for avoiding any occlusal interference. TMJ sound faded away and a standard [formula: see text] extraction treatment was completed for crowding correction and better occlusion.
