Olivier Pérez | Searcharxiv

arXiv2020

Weak localization competes with the quantum oscillations in a natural electronic superlattice: the case of Na$_{1.5}$(PO$_2$)$_4$(WO$_3$)$_{20}$

We report an investigation of the combined structural and electronic properties of the bronze Na$_{1.5}$(PO$_{2}$)$_{4}$(WO$_{3}$)$_{20}$. Its low dimensional structure and possible large reconstruction of the Fermi surface due to charge density wave instability makes this bulk material a natural superlattice with a reduced number of carriers and Fermi energy. Signatures of multilayered 2D electron weak localization are consequently reported, with an enhanced influence of quantum oscillations. A crossover between these two antagonistic entities previously observed only in genuine low dimensional materials and devices, is shown to occur in a bulk crystal due to its hidden 2D nature.

cond-mat.str-el↗

arXiv2016

Detailed investigation of the phase transition in K$_{x}$P$_4$W$_{8}$O$_{32}$ and experimental arguments for a charge density wave due to hidden nesting

Detailed structural and magnetotransport properties of the monophosphate tungsten bronze K$_{x}$P$_4$W$_{8}$O$_{32}$ single crystals are reported. Both galvanomagnetic and thermal properties are shown to be consistent with a charge density wave electronic transition due to hidden nesting of quasi - 1D portion of the Fermi surface. We also observe the enhancement of electronic anisotropy due to reconstruction of the Fermi surface at the Peierls transition. The resistivity presents a thermal hysteresis suggesting a first order nature characteristics of a strong coupling scenario. However, other measurements such as the change of carriers density demonstrate a second order Peierls scenario with weak coupling features. We suggest that the structural transition driven by the residual strain in the K - P - O environment is responsible for the resistivity hysteresis and modifes the Fermi surface which then helps the rise to the second order Peierls instability.

cond-mat.str-el↗