Unconventional Transport Properties of Reduced Tungsten Oxide WO2.9

Condensed Matter

Alexander Shengelaya¹  Kazimierz Conder²  FabioLa Mattina³ 

[1] Department of Physics, Ivane Javakhishvili Tbilisi State University, Chavchavadze 3, GE-0128 Tbilisi, Georgia;Laboratory for Multiscale Materials Experiments, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland;Laboratory for Transport at Nanoscale Interfaces, Empa Swiss Federal Laboratories for Science and Technology, 8600 Dübendorf, Switzerland;

关键词: tungsten oxide;    polarons;    superconductivity;   

DOI  :  10.3390/condmat5040063

来源: DOAJ

【 摘 要 】

The temperature and magnetic field dependence of resistivity in WO_2.9 was investigated. The variation of resistivity with temperature displayed unusual features, such as a broad maximum around 230 K and a logarithmic increase of resistivity below 16 K. In the temperature range 16–230 K, we observed metallic-like behavior with a positive temperature coefficient. The combined analysis of resistivity and magnetoresistance (MR) data shows that these unusual transport properties of WO_2.9 can be understood by considering the (bi)polaronic nature of charge carriers. In contrast to magnetization data, superconducting transition below T_c = 80 K was not detected in resistivity measurements, indicating that the superconductivity is localized in small regions that do not percolate. We found a strong increase in positive MR below 80 K. This effect is similar to that observed in underdoped cuprates, where the substantial increase of MR is attributed to superconducting fluctuations in small clusters. Therefore, the temperature dependence of MR indicates the presence of non-percolating superconducting clusters in WO_2.9 below 80 K in agreement with magnetization data.

【 授权许可】

Unknown