分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-08
Tan, XJ [Tan, Xiaojian][ 1 ]
Shao, HZ [Shao, Hezhu][ 1 ]
Hu, TQ [Hu, Tianqi][ 1 ]
Liu, GQ [Liu, Guoqiang][ 1 ]
Jiang, J [Jiang, Jun][ 1 ]
Jiang, HC [Jiang, Haochuan][ 1 ]
摘要： The thermoelectric properties of two-dimensional graphyne sheets are investigated by using first- principles calculations and the Boltzmann transport equation method. The electronic structure indicates a semiconducting phase for graphyne, compared with the metallic phase of graphene. Consequently, the obtained Seebeck coefficient and the power factor of graphyne are much higher than those of graphene. The calculated phonon mean free path for graphene is 866 nm, which is in good agreement with the experimental value of 775 nm. Meanwhile the phonon mean free path of graphyne is only 60 nm, leading to two order lower thermal conductivity than graphene. We show that the low thermal conductivity of graphyne is due to its mixed sp/sp2 bonding. Our calculations show that the optimized ZT values of graphyne sheets can reach 5.3 at intermediate temperature by appropriate doping.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-02
Xu, JT [Xu, Jingtao][ 1 ]
Wu, JZ [Wu, Jiazhen][ 2 ]
Shao, HZ [Shao, Hezhu][ 1 ]
Heguri, S [Heguri, Satoshi][ 2 ]
Tanabe, YC [Tanabe, Yoichi][ 3 ]
Liu, YF [Liu, Yongfu][ 1 ]
Liu, GQ [Liu, Guo-Qiang][ 1 ]
Jiang, J [Jiang, Jun][ 1 ]
Jiang, HC [Jiang, Haochuan][ 1 ]
Tanigaki, K [Tanigaki, Katsumi][ 2,3 ]
摘要： We study type I clathrate Ba8Cu5.1Ge40.2Sn0.7 single crystals (space group Pm3"n, no. 223, a 1⁄4 10.7151(3)) grown using a Sn flux method. Microprobe analysis and single-crystal X-ray diffraction reveal a small amount of Sn embedded in the Cu/Ge framework, which increases disorder at the guest Ba sites. Ba8Cu5.1Ge40.2Sn0.7 is diamagnetic with a susceptibility of $2.8 10 7 emu g 1 and shows metal-like behavior (dr/dT > 0) with a low charge carrier concentration of 0.5 e per unit cell at 300 K. The single crystals show a relatively high carrier mobility (m (300 K) 1⁄4 11.9 cm2 V 1) and very low lattice thermal conductivity ($0.6 W m 1 K 1). The thermoelectric figure of merit ZT of Ba8Cu5.1Ge40.2Sn0.7 single crystals reaches a maximum value of 0.6 at 773 K, which can be further improved by adjusting the chemical composition.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-02
He, J [He, Jun][ 1,2 ]
Xu, JT [Xu, Jingtao][ 1 ]
Liu, GQ [Liu, Guoqiang][ 1 ]
Tan, XJ [Tan, Xiaojian][ 1 ]
Shao, HZ [Shao, Hezhu][ 1 ]
Liu, Z [Liu, Zhu][ 1 ]
Xu, JQ [Xu, Jiaqiang][ 2 ]
Jiang, J [Jiang, Jun][ 1 ]
Jiang, HC [Jiang, Haochuan][ 1 ]
摘要： Tin telluride (SnTe) has recently attracted much attention as a promising thermoelectric material. In this work, SnTe is alloyed with additional Pb, and the high density crystalline ingots of SnPbxTe (x 1⁄4 0, 0.02, 0.04, and 0.06) have been synthesized by a zone-melting method. Through this method, SnPbxTe samples show larger power factors than those prepared by other methods, and a maximum value of 30.5 mW cm 1 K 2 at 823 K has been reached in p-type SnPb0.02Te, which is the highest value reported so far. As a result, a promising figure of merit ZT of $0.81 has been obtained at 823 K.
提交时间： 2017-05-02
Shao, HZ [Shao, Hezhu][ 1 ]
Tan, XJ [Tan, Xiaojian][ 1 ]
Hu, TQ [Hu, Tianqi][ 1 ]
Liu, GQ [Liu, Guo-Qiang][ 1 ]
Jiang, J [Jiang, Jun][ 1 ]
Jiang, HC [Jiang, Haochuan][ 1 ]
摘要： principles calculations. The obtained phonon frequencies agree well with the measurements of Raman scattering. The thermodynamic properties are calculated within quasi-harmonic approximation, and the measured lattice thermal conductivity is well reproduce
提交时间： 2017-05-02
Chen, L [Chen, Liang][ 1 ]
Shao, HZ [Shao, Hezhu][ 1 ]
Zhou, XF [Zhou, Xufeng][ 1 ]
Liu, GQ [Liu, Guoqiang][ 1 ]
Jiang, J [Jiang, Jun][ 1 ]
Liu, ZP [Liu, Zhaoping][ 1 ]
摘要： Rechargeable aqueous metal-ion batteries made from non-flammable and low-cost materials offer promising opportunities in large-scale utility grid applications, yet low voltage and energy output, as well as limited cycle life remain critical drawbacks in t
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