Evidence of nested quasi-one-dimensional Fermi surface and decoupled charge-lattice orders in layered TaTe2

Y. Lin, M. Huber, K. M. Siddiqui, L. Moreschini, P. Ai, S. Rajpurohit, L. Tan, j.D. Denlinger, A Lanzara, D. H. Eilbott, L Moreschini, Y.L. Zhu, Z.Q. Mao

The formations of charge and lattice orders are generally coupled in charge density wave (CDW) materials. Although this situation is usually satisfied in a large class of two. dimensional materials, it falls short in describing the so-called CDW-like phase transition in layered TaTe, accompanied by anomalous low temperature transport properties and a periodic lattice distortion. Prof. Lanzara' group at Lawrence Berkeley National Laboratory recently studied the anomalous CDW phase transition of TaTe using APES and low-energy electron diffraction. Their data reveal the presence of a surprising quasi- one-dimensional Fermi surface with nesting condition. They find that the wave vectors of the Fermi surface nesting and periodic lattice distortion are different, suggesting the decoupled formation between charge and lattice orders. This work provides routes for forging unconventional CW phases and charge- lattice entanglement that would otherwise not be available in materials with fixed dimensionality.