Charge fluctuations above <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>T</mml:mi><mml:mtext>CDW</mml:mtext></mml:msub></mml:math> revealed by glasslike thermal transport in kagome metals <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>A</mml:mi><mml:msub><mml:mrow><mml:mi mathvariant="normal">V</mml:mi></mml:mrow><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mi>Sb</mml:mi></mml:mrow><mml:mn>5</mml:mn></mml:msub></mml:math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mo>(</mml:mo><mml:mi>A</mml:mi><mml:mo>=</mml:mo><mml:mi mathvariant="normal">K</mml:mi><mml:mo>,</mml:mo><mml:mi>Rb</mml:mi><mml:mo>,</mml:mo><mml:mi>Cs</mml:mi><mml:mo>)</mml:mo></mml:math>
Kunya Yang, Wei Xia, Xinrun Mi, Long Zhang, Yuhan Gan, Aifeng Wang, Yisheng Chai, Xiaoyuan Zhou, Xiaolong Yang, Yanfeng Guo, Mingquan He
Abstract
We present heat capacity, electrical, and thermal transport measurements of kagome metals $A{\mathrm{V}}_{3}{\mathrm{Sb}}_{5}$ $(A=\mathrm{K},\mathrm{Rb},\mathrm{Cs})$. In all three compounds, the development of short-range charge fluctuations above the charge density wave (CDW) transition temperature ${T}_{\mathrm{CDW}}$ strongly scatters phonons via the electron-phonon coupling, leading to the glasslike phonon heat transport, i.e., the phonon thermal conductivity decreases weakly upon cooling. Once the long-range charge order sets in below ${T}_{\mathrm{CDW}}$, short-range charge fluctuations are quenched, and the typical Umklapp scattering dominated phonon heat transport is recovered. The charge-fluctuations-induced glasslike phonon thermal conductivity implies sizable electron-phonon coupling in $A{\mathrm{V}}_{3}{\mathrm{Sb}}_{5}$.