Infrared properties of W-doped charge-density-wave material K$_{0.3}$MoO$_3$

TL;DR

This study investigates the infrared optical properties of W-doped K$_{0.3}$MoO$_3$, revealing persistent optical gaps despite doping that suppresses the charge-density-wave transition, challenging existing theories.

Contribution

It provides new insights into how tungsten doping affects the optical conductivity and charge-density-wave behavior in K$_{0.3}$MoO$_3$.

Findings

Optical gap persists at ~0.2 eV despite heavy W doping.

W doping suppresses the CDW transition as seen in resistivity.

Impurity effects challenge current understanding of CDW and optical gap relationship.

Abstract

The optical conductivity spectra of quasi-one dimensional compounds K$_{0.3}$Mo$_{1-x}$W$_x$O$_3$ (x=0, 0.03 and 0.15) have been studied over broad frequencies. While the dc resistivity measurements indicate no sign of CDW transition in heavily W-doped blue bronze, the optical conductivity spectra still show a single particle gap at around 0.2 eV for \textbf{E} parallel to the chain direction. Such impurity effect challenges our understanding about the occurrence of the optical gap with the CDW transition.