上海科技大学知识管理系统

Although the concept of Luttinger liquid (LL) that describes a one-dimensional (1D) interacting fermion system1,2 collapses in higher dimensions, it has been proposed to be closely related to many mysteries including the normal state of cuprate superconductor3-5, unconventional metal6,7, and quantum criticality8,9. Therefore, the generalization of LL model to higher dimensions has attracted substantial research attention4,10-12. Here we systematically investigate the electronic structure of a quasi-2D compound η-Mo4O11 using high-resolution angle-resolved photoemission spectroscopy and ab-initio calculation. Remarkably, we reveal a prototypical LL behavior originated from the crossing quasi-1D chain arrays hidden in the quasi-2D crystal structure. Our results suggest that η-Mo4O11 materializes the long sought-after crossed LL phase13-15, where the orthogonal orbital components significantly reduce the coupling between intersecting quasi-1D chains and therefore maintain the essential properties of LL. Our finding not only presents a realization of 2D LL, but also provides a new angle to understand non-Fermi liquid behaviors in other 2D and 3D quantum materials.