New evidence of an anomalous phase of matter brings energy-efficient technologies closer

Phys.org  July 14, 2021
An international team of researchers (UK, Japan, Slovenia, India, USA – Columbia University, Switzerland) used ultrafast pump-probe microscopy to investigate the possible excitonic insulator Ta2NiSe5. Below 328 K, they observed the anomalous micrometer-scale propagation of coherent modes at velocities of ~105 m/s, which they attributed to the hybridization between phonon modes and the phase mode of the condensate. They developed a theoretical framework to support this explanation and proposed that electronic interactions provide a substantial contribution to the ordered phase in Ta2NiSe5. These results allow us to understand how the condensate’s collective modes transport energy and interact with other degrees of freedom. The study provides a unique paradigm for the investigation and manipulation of these properties in strongly correlated materials. Harnessing its properties could pave the way to new technologies able to share information without energy losses…read more. Open Access TECHNICAL ARTICLE 

Time-dependent mean-field model. Credit: Science Advances 07 Jul 2021, Vol. 7, no. 28, eabd6147