Charge density wave with anomalous temperature dependence in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>UPt</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Si</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>
Jooseop Lee, K. Prokeš, Sohee Park, Igor Zaliznyak, Sachith Dissanayake, Masaaki Matsuda, Matthias Frontzek, Stanislav Stoupin, Greta Chappell, Ryan Baumbach, Changwon Park, J. A. Mydosh, G. E. Granroth, Jacob P. C. Ruff
Abstract
Using single-crystal neutron and x-ray diffraction, we discovered a charge density wave (CDW) below 320 K, which accounts for the long-sought origin of the heat capacity and resistivity anomalies in ${\mathrm{UPt}}_{2}{\mathrm{Si}}_{2}$. The modulation wave vector, ${\mathbit{Q}}_{\mathrm{mod}}$, is intriguingly similar to the incommensurate wave vector of ${\mathrm{URu}}_{2}{\mathrm{Si}}_{2}$. ${\mathbit{Q}}_{\mathrm{mod}}$ shows an unusual temperature dependence, shifting from commensurate to incommensurate position upon cooling and becoming locked at aproximately (0.42 0 0) near 180 K. Bulk measurements indicate a crossover toward a correlated coherent state around the same temperature, suggesting an interplay between the CDW and Kondo-lattice-like coherence before coexisting antiferromagnetic order sets in at ${T}_{\mathrm{N}}=35$ K.