Heteroatom-doping is a promising strategy to tuning the microstructure of carbon material toward improved electrochemical storage performance. However, it is a big challenge to control the doping sites for heteroatom-doping and the rational design of doping is urgently needed. Herein, S doping sites and the influence of interlayer spacing for two kinds of hard carbon, perfect structure and vacancy defect structure, are explored by the first-principles method. S prefers doping in the interlayer for the former with interlayer distance of 3.997 Å, while S is doped on the carbon layer for the latter with interlayer distance of 3.695 Å. More importantly, one step molten salts method is developed as a universal synthetic strategy to fabricate hard carbon with tunable microstructure. It is demonstrated by the experimental results that S-doping hard carbon with fewer pores exhibits a larger interlayer spacing than that of porous carbon, agreeing well with the theoretical prediction. Furthermore, the S-doping carbon with larger interlayer distance and fewer pores exhibits remarkably large reversible capacity, excellent rate performance, and long-term cycling stability for Na-ion storage. A stable and reversible capacity of ≈200 mAh g is steadily kept even after 4000 cycles at 1 A g .

A highly (100) oriented GeSe thin film was deposited by evaporation and novel sandwiching post-annealing, achieving a device with a high VOC.

Extreme magnetoresistance in nonmagnetic compounds has received considerable attention because this phenomenon challenges the classical understanding of electron transport under a magnetic field.

Inconceivably large changes (up to 10 6 %) of the resistivity induced by external magnetic field-a phenomenon known as the extreme magnetoresistance effect has been reported in a great number of exotic semimetals. The very recent and exciting discoveries mainly pay attention to the compounds without magnetic ground states, which appears to limit the potential growth of semimetal family. For fundamental scientific interests, introduction of spin degree of freedom would provide an almost ideal platform for investigating the correlation effect between magnetism, crystallographic structure and electric resistivity in materials. Here, we report the experimental observation of metamagnetic behaviors and transport properties of HoBi single crystals. Being a magnetic member of the rare earth monopnictide family, the magnetoresistance of HoBi is significantly modulated by the magnetic orders at low temperature, which shows a nonmonotonic increment across the successive magnetic phases and reaches 10 4 % (9 T and 2 K) in the ferromagnetic state. Kohler's rule predicts that more than one type of carriers dominates the transport properties. Well fitted magnetoresistance and Hall resistivity curves by the semiclassical two-band model suggest that the densities of electron and hole carriers are nearly compensated and the carrier mobilities in this compound are ultrahigh. Besides, the inverted band structures and nonzero Z 2 topological invariant indicate that possible nontrivial electronic states could generate in the ferromagnetic phase of HoBi. Combining the experimental and theoretical results, it is found that the cooperative action of carrier compensation effect and ultrahigh mobility might contribute to the extreme magnetoresistance observed in the titled compound. These findings suggest a paradigm for obtaining the extreme magnetoresistance in magnetic compounds and are relevant to understand the rare-earth-based correlated topological materials. tunnel magnetoresistance [2-5], extremely large magnetoresistance have attracted increasing interest [6, 7], since it not only offer the potential to design new devices, but also pose challenges to understand the fundamental phenomena in nature. The extreme magnetoresistance has been widely reported in the classic elemental semimetal Bi, topological semimetals WTe 2 , Cd 3 As 2 , TaPn (Pn = As, Sb) family, pyrite-type PtBi 2 , RPtBi (R=Nd, Gd), RPn (R=rare earth; Pn = Sb, Bi) and so on . Ever since the unprecedentedly large magnetoresistance is revealed in LaSb, the research enthusiasm on rare earth monopnictides RPn (R=rare earth, Pn = Sb, Bi) is inspired [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. The family has been widely studied in the 1980-90s for its heavy-fermion nature [31]. Intriguingly, the recent calculations predict that LaPn (Pn = N, P, As, Sb, and Bi) could be a topological prototype material with band inversion at X point of the bulk fcc Brillouin zone [32]. Afterwards, further investigation on this family has been systematically performe...

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Synergic effect of electronic correlation and spin-orbit coupling is an emerging topic in topological materials. Central to this rapidly developing area are the prototypes of strongly correlated heavy-fermion systems. Recently, some Ce-based compounds are proposed to host intriguing topological nature, among which the electronic properties of CeSb are still under debate. In this paper, we report a comprehensive study combining magnetic and electronic transport measurements, and electronic band structure calculations of this compound to identify its topological nature. Quantum oscillations are clearly observed in both magnetization and magnetoresistance at high fields, from which one pocket with a nontrivial Berry phase is recognized. Angular-dependent magnetoresistance shows that this pocket is elongated in nature and corresponds to the electron pocket as observed in LaBi.Nontrivial electronic structure of CeSb is further confirmed by first-principle calculations, which arises from spin splitting in the fully polarized ferromagnetic state.These features indicate that magnetic-field can induce nontrivial topological electronic states in this prototypical Kondo semimetal.

The electronic structure and charge transfer of Bi2Te2Se and Bi2Se2Te thin films are robust to an external electrical field.

Phosphate group-doped blue TiO2(B) nanowires were first achieved, exhibiting ultra-fast and ultra-stable sodium storage.