Charge Density Wave Transition in (PbSe)(1+delta)(VSe2)(n) Compounds with n=1, 2, and 3

摘要

A series of (PbSe)(1+delta)(VSe2)(n) heterostructures with extensive turbostratic disorder were synthesized with n = 1-3 through low temperature annealing of appropriately designed layered precursors. The crystal structures consist of alternating layers of CdI2 type structured VSe2 and distorted NaCl type structured PbSe. The n = 1 compound has a positive Hall coefficient and a charge density wave like transition at 100 K, during which the resistivity increases by a factor of 3.5 and the Hall coefficient increases by a factor of 8. The n = 2 and 3 compounds have negative Hall coefficients and significantly smaller changes in the slope of the resistivity and Hall coefficient as a function of temperature at similar temperatures. The distinctly different transport properties of the compound containing a monolayer of VSe2 compared to compounds with thicker VSe2 layers highlights the complexity of the electronic structure of these stacked systems. The differences cannot be simply explained by charge transfer between VSe2 and PbSe within a rigid band model. More sophisticated interactions between the constituent layers, electron phonon interactions, and/or correlation between electrons need to be considered to explain the change in carrier type and the charge density wave (CDW) transition.