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Yuping Sun

Bio: Yuping Sun is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Thin film & Magnetization. The author has an hindex of 48, co-authored 521 publications receiving 9721 citations. Previous affiliations of Yuping Sun include University of Science and Technology of China & Anhui University.


Papers
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TL;DR: In this article, a modified chemical coprecipitation route was used to synthesize CoFe 2 O 4 ferrite nanoparticles, and structural and magnetic properties were systematically investigated.

290 citations

Journal ArticleDOI
TL;DR: In this article, 3D interconnected networks of 1T-MoS2/Ti3C2 MXene heterostructures are constructed by magneto-hydrothermal synthesis, and the electrochemical storage mechanisms are investigated.
Abstract: 2D/2D heterostructures can combine the collective advantages of each 2D material and even show improved properties from synergistic effects. 2D Transition metal carbide Ti3C2 MXene and 2D 1T-MoS2 have emerged as attractive prototypes in electrochemistry due to their rich properties. Construction of these two 2D materials, as well as investigation about synergistic effects, is absent due to the instability of 1T-MoS2. Here, 3D interconnected networks of 1T-MoS2/Ti3C2 MXene heterostructure are constructed by magneto-hydrothermal synthesis, and the electrochemical storage mechanisms are investigated. Improved extra capacitance is observed due to enlarged ion storage space from a synergistically interplayed effect in 3D interconnected networks. Outstanding rate performance is realized because of ultrafast electron transport originating from Ti3C2 MXene. This work provides an archetype to realize excellent electrochemical properties in 2D/2D heterostructures.

281 citations

Journal ArticleDOI
TL;DR: In this article, the effect of the uniaxial strain on the thermoelectric properties of phosphorene was investigated by using the first-principles calculations combined with the semiclassical Boltzmann theory.
Abstract: The newly emerging monolayer phosphorene was recently predicted to be a promising thermoelectric material. In this work, we propose to further enhance the thermoelectric performance of phosphorene using the strain-induced band convergence. The effect of the uniaxial strain on the thermoelectric properties of phosphorene was investigated by using the first-principles calculations combined with the semiclassical Boltzmann theory. When the zigzag-direction strain is applied, the Seebeck coefficient and electrical conductivity in the zigzag direction can simultaneously be greatly enhanced at the critical strain of 5%, at which the band convergence is achieved. The largest $ZT$ value of 1.65 at 300 K is then conservatively estimated by using the bulk lattice thermal conductivity. When the armchair-direction strain of 8% is applied, the room-temperature $ZT$ value can reach 2.12 in the armchair direction of phosphorene. Our results indicate that strain-induced band convergence could be an effective method to enhance the thermoelectric performance of phosphorene.

257 citations

Journal ArticleDOI
TL;DR: It is demonstrated that the intrinsic properties of atomically thin flakes are preserved by encapsulation with hexagonal boron nitride in inert atmosphere and this facile assembly method is used together with transmission electron microscopy and transport measurements to probe the nature of the 2D state and show that its conductance is dominated by discommensurations.
Abstract: The layered transition metal dichalcogenides host a rich collection of charge density wave phases in which both the conduction electrons and the atomic structure display translational symmetry breaking. Manipulating these complex states by purely electronic methods has been a long-sought scientific and technological goal. Here, we show how this can be achieved in 1T-TaS2 in the 2D limit. We first demonstrate that the intrinsic properties of atomically thin flakes are preserved by encapsulation with hexagonal boron nitride in inert atmosphere. We use this facile assembly method together with transmission electron microscopy and transport measurements to probe the nature of the 2D state and show that its conductance is dominated by discommensurations. The discommensuration structure can be precisely tuned in few-layer samples by an in-plane electric current, allowing continuous electrical control over the discommensuration-melting transition in 2D.

209 citations

Journal ArticleDOI
TL;DR: In this paper, the authors reported the greatly enhanced thermoelectric performance of a ZrS2 monolayer by the biaxial tensile strain, due to the simultaneous increase of the Seebeck coefficient and decrease of the thermal conductivity.
Abstract: The increase of a thermoelectric material's figure of merit (ZT value) is limited by the interplay of the transport coefficients. Here we report the greatly enhanced thermoelectric performance of a ZrS2 monolayer by the biaxial tensile strain, due to the simultaneous increase of the Seebeck coefficient and decrease of the thermal conductivity. Based on first-principles calculations combined with the Boltzmann transport theory, we predict that the band structure of the ZrS2 monolayer can be effectively engineered by the strain, and the Seebeck coefficient is significantly increased. The thermal conductivity is reduced by the applied tensile strain due to the phonon softening. At the strain of 6%, the maximum ZT value of 2.4 is obtained for the p-type doped ZrS2 monolayer at 300 K, which is 4.3 times larger than that of the unstrained system. Moreover, the temperature dependence of the ZT values is investigated, and compared with the unstrained system, the ZT values of the p- and n-type doping are much more balanced by the applied strain.

191 citations


Cited by
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TL;DR: In this article, the authors examined the methods used to synthesize transition metal dichalcogenides (TMDCs) and their properties with particular attention to their charge density wave, superconductive and topological phases, along with their applications in devices with enhanced mobility and with the use of strain engineering to improve their properties.
Abstract: Graphene is very popular because of its many fascinating properties, but its lack of an electronic bandgap has stimulated the search for 2D materials with semiconducting character. Transition metal dichalcogenides (TMDCs), which are semiconductors of the type MX2, where M is a transition metal atom (such as Mo or W) and X is a chalcogen atom (such as S, Se or Te), provide a promising alternative. Because of its robustness, MoS2 is the most studied material in this family. TMDCs exhibit a unique combination of atomic-scale thickness, direct bandgap, strong spin–orbit coupling and favourable electronic and mechanical properties, which make them interesting for fundamental studies and for applications in high-end electronics, spintronics, optoelectronics, energy harvesting, flexible electronics, DNA sequencing and personalized medicine. In this Review, the methods used to synthesize TMDCs are examined and their properties are discussed, with particular attention to their charge density wave, superconductive and topological phases. The use of TMCDs in nanoelectronic devices is also explored, along with strategies to improve charge carrier mobility, high frequency operation and the use of strain engineering to tailor their properties. Two-dimensional transition metal dichalcogenides (TMDCs) exhibit attractive electronic and mechanical properties. In this Review, the charge density wave, superconductive and topological phases of TMCDs are discussed, along with their synthesis and applications in devices with enhanced mobility and with the use of strain engineering to improve their properties.

3,436 citations

01 Sep 1955
TL;DR: In this paper, the authors restrict their attention to the ferrites and a few other closely related materials, which are more closely related to anti-ferromagnetic substances than they are to ferromagnetics in which the magnetization results from the parallel alignment of all the magnetic moments present.
Abstract: In this chapter, we will restrict our attention to the ferrites and a few other closely related materials. The great interest in ferrites stems from their unique combination of a spontaneous magnetization and a high electrical resistivity. The observed magnetization results from the difference in the magnetizations of two non-equivalent sub-lattices of the magnetic ions in the crystal structure. Materials of this type should strictly be designated as “ferrimagnetic” and in some respects are more closely related to anti-ferromagnetic substances than they are to ferromagnetics in which the magnetization results from the parallel alignment of all the magnetic moments present. We shall not adhere to this special nomenclature except to emphasize effects, which are due to the existence of the sub-lattices.

2,659 citations