RESUMEN
Two-dimensional (2D) van der Waals heterostructures endow individual 2D material with the novel functional structures, intriguing compositions, and fantastic interfaces, which efficiently provide a feasible route to overcome the intrinsic limitations of single 2D components and embrace the distinct features of different materials. However, the construction of 2D heterostructures with uniform heterointerfaces still poses significant challenges. Herein, a universal in-situ interfacial growth strategy is designed to controllably prepare a series of MXene-based tin selenides/sulfides with 2D van der Waals homogeneous heterostructures. Molten salt etching by-products that are usually recognized as undesirable impurities, are reasonably utilized by us to efficiently transform into different 2D nanostructures via in-situ interfacial growth. The obtained MXene-based 2D heterostructures present sandwiched structures and lamellar interlacing networks with uniform heterointerfaces, which demonstrate the efficient conversion from 3D composite to 2D heterostructures. Such 2D heterostructures significantly enhance charge transfer efficiency, chemical reversibility, and overall structural stability in the electrochemical process. Taking 2D-SnSe2/MXene anode as a representative, it delivers outstanding lithium storage performance with large reversible capacities and ultrahigh capacity retention of over 97% after numerous cycles at 0.2, 1.0, and 10.0 A g-1 current density, which suggests its tremendous application potential in lithium-ion batteries.
RESUMEN
The strong spin-orbit coupling and the broken inversion symmetry in monolayer transition metal dichalcogenides results in spin-valley coupled band structures. Such a band structure leads to novel applications in the fields of electronics and optoelectronics. Density functional theory calculations as well as optical experiments have focused on spin-valley coupling in the valence band. Here we present magnetotransport experiments on high-quality n-type monolayer molybdenum disulphide (MoS_{2}) samples, displaying highly resolved Shubnikov-de Haas oscillations at magnetic fields as low as 2 T. We find the effective mass 0.7m_{e}, about twice as large as theoretically predicted and almost independent of magnetic field and carrier density. We further detect the occupation of the second spin-orbit split band at an energy of about 15 meV, i.e., about a factor of 5 larger than predicted. In addition, we demonstrate an intricate Landau level spectrum arising from a complex interplay between a density-dependent Zeeman splitting and spin- and valley-split Landau levels. These observations, enabled by the high electronic quality of our samples, testify to the importance of interaction effects in the conduction band of monolayer MoS_{2}.
RESUMEN
InSb, a narrow-band III-V semiconductor, is known for its small bandgap, small electron effective mass, high electron mobility, large effectiveg-factor, and strong spin-orbit interactions. These unique properties make InSb interesting for both industrial applications and quantum information processing. In this paper, we provide a review of recent progress in quantum transport research on InSb quantum well devices. With advancements in the growth of high-quality heterostructures and micro/nano fabrication, quantum transport experiments have been conducted on low-dimensional systems based on InSb quantum wells. Furthermore, ambipolar operations have been achieved in undoped InSb quantum wells, allowing for a systematic study of the band structure and quantum properties of p-type narrow-band semiconductors. Additionally, we introduce the latest research on InAsSb quantum wells as a continuation of exploring physics in semiconductors with even narrower bandgaps.