Embedded Files
Correlated Topological System
Wei-Chi Chiu, Guoqing Chang, Gennevieve Macam, Ilya Belopolski, Shin-Ming Huang, Robert Markiewicz, Jia-Xin Yin, Zi-jia Cheng, Chi-Cheng Lee, Tay-Rong Chang, Feng-Chuan Chuang, Su-Yang Xu, Hsin Lin, M. Zahid Hasan, Arun Bansil
Nature Communications 14, 2228 (2023)
The spacetime light cone is central to the definition of causality in the theory of relativity. Recently, links between relativistic and condensed matter physics have been uncovered, where relativistic particles can emerge as quasiparticles in the energy-momentum space of matter. Here, we unveil an energy-momentum analogue of the spacetime light cone by mapping time to energy, space to momentum, and the light cone to the Weyl cone. We show that two Weyl quasiparticles can only interact to open a global energy gap if they lie in each other’s energy-momentum dispersion cones–analogous to two events that can only have a causal connection if they lie in each other’s light cones. Moreover, we demonstrate that the causality of surface chiral modes in quantum matter is entangled with the causality of bulk Weyl fermions. Furthermore, we identify a unique quantum horizon region and an associated ‘thick horizon’ in the emergent causal structure.
In the news: Northeastern Global News, Phys.org
Wei-Chi Chiu, Sougata Mardanya, Robert Markiewicz, Jouko Nieminen, Bahadur Singh, Tugrul Hakioglu, Amit Agarwal, Tay-Rong Chang, Hsin Lin, Arun Bansil
Emergence of topological states in strongly correlated systems, particularly two- dimensional (2D) transition-metal dichalcogenides, presents unique opportunities for manipulating electronic properties in quantum materials. However, a comprehensive understanding of the intricate interplay between correlations and topology remains elusive. Here we employ first-principles modeling to reveal two distinct 2×2 charge density wave (CDW) phases in monolayer 1H-NbSe2, which become energetically favorable over the conventional 3×3 CDWs under modest biaxial tensile strain of about 1%. These strain-induced CDW phases coexist with numerous topological states characterized by Z2 topology, high mirror Chern numbers, topological nodal lines, and higher-order topo- logical states, which we have verified rigorously by computing the topological indices and the presence of robust edge states and localized corner states. Remarkably, these topological properties emerge because of the CDW rather than a pre-existing topology in the pristine phase. Our findings advance the fundamental understanding of the interplay between correlations, topology, and geometry in 2D materials, opening new opportunities to engineer topological states through strain-induced correlation effects in materials with initially trivial topology. These results hold promise for applications in electronics, spintronics, and other advanced quantum devices, where robust and tunable topological states are crucial.
Page updated
Google Sites
Report abuse