JiHui Yang

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Skutterudites CoSb(3) with multiple cofillers Ba, La, and Yb were synthesized and very high thermoelectric figure of merit ZT = 1.7 at 850 K was realized. X-ray diffraction of the densified multiple-filled bulk samples reveals all samples are phase pure. High-resolution scanning transmission electron microscopy (STEM) and energy dispersive X-ray(More)
We adopt a global optimization method to predict two-dimensional (2D) nanostructures through the particle-swarm optimization (PSO) algorithm. By performing PSO simulations, we predict new stable structures of 2D boron-carbon (B-C) compounds for a wide range of boron concentrations. Our calculations show that: (1) All 2D B-C compounds are metallic except for(More)
Understanding thermal and phonon transport in solids has been of great importance in many disciplines such as thermoelectric materials, which usually requires an extremely low lattice thermal conductivity (LTC). By analyzing the finite-temperature structural and vibrational characteristics of typical thermoelectric compounds such as filled skutterudites and(More)
J. Zhang, Dr. R. Liu, N. Cheng, Dr. Y. Zhang, Prof. X. Shi, Prof. L. Chen, Prof. W. Zhang State Key Laboratory of High Performance Ceramics and Superfi ne Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences, 1295 Dingxi Road Shanghai 200050 , China E-mail: xshi@mail.sic.ac.cn; cld@mail.sic.ac.cn; wqzhang@mail.sic.ac.cn J. Zhang, N.(More)
Intriguing experimental results raised the question about the fundamental mechanisms governing the electron-hole coupling induced bipolar thermal conduction in semiconductors. Our combined theoretical analysis and experimental measurements show that in semiconductors bipolar thermal transport is in general a "conductivity-limiting" phenomenon, and it is(More)
Adsorption of hydrogen molecules on platinum-doped single-walled zigzag (8,0) boron nitride (BN) nanotube is investigated using the density-functional theory. The Pt atom tends to occupy the axial bridge site of the BN tube with the highest binding energy of -0.91 eV. Upon Pt doping, several occupied and unoccupied impurity states are induced, which reduces(More)
We investigate vibrational behaviors in misch-metal filled antimony skutterudites in the time domain. At higher filling ratios of guest atoms, the vibration frequency approaches that of the cage structure and the amplitude becomes stronger. Furthermore, the reduction of lattice thermal conductivity over a wide temperature range can be explained using the(More)
A recent report of highly unusual ferroelectric fluctuations in PbTe by E. S. Božin et al. [Science 330, 1660 (2010)] raises fundamental questions about the nature of underlying lattice dynamics. We show by first-principles calculations that the reported results can be attributed to abnormally large-amplitude thermal vibrations that stem from a delicate(More)
Many recent advances in thermoelectric (TE) materials are attributed to their nanoscale constituents. Determination of the nanocomposite structures has represented a major experimental and computational challenge and eluded previous attempts. Here we present the first atomically resolved structures of high performance TE material PbTe-AgSbTe2 by(More)