박사과정 김진희의 논문이 Physical Review B에 출판되었습니다.
제목: Small-polaron transport and thermoelectric properties of the misfit-layer composite
(BiSe)1.09TaSe2/TaSe2
초록: We studied the thermoelectric properties of the composite of misfit-layered compounds (BiSe)1.09TaSe2 and TaSe2. The x-ray diffraction pattern on the cross-sectional plane of the sintered body shows a preferred orientation of the (00l) direction for (BiSe)1.09TaSe2/TaSe2 indicating anisotropic alignment during hot pressing. Because of the crystallographic alignment, the temperature-dependent electrical resistivity ρ(T ), Seebeck coefficient S(T ), and the thermal conductivity κ(T ) exhibit in-plane and out-of-plane anisotropic transport behavior. The Seebeck
coefficient is very low because of the coexistence of electron and hole mixing, as confirmed by the two-carrier model. The lattice thermal conductivity κL of the covalent bonding layer (in-plane) is lower than those of the layer with van der Waals bonding (out-of-plane) implying the existence of a charge density wave along the in-plane. We observed a sign anomaly of the positive Hall coefficient RH and negative Seebeck coefficient S. According to Holstein’s small-polaron model, the sign anomaly may come from the odd number of small-polaron hopping sites.
URL: http://link.aps.org/doi/10.1103/PhysRevB.87.224305
DOI: 10.1103/PhysRevB.87.224305
조회 : 5,983
