Carrier-Density Control of the Quantum-Confined 1$T$-TiSe$_2$ Charge-Density-Wave
cond-mat.mtrl-sci
/ Authors
T. Jaouen, A. Pulkkinen, M. Rumo, G. Kremer, B. Salzmann, C. W. Nicholson, M. -L. Mottas, E. Giannini, S. Tricot, P. Schieffer
and 2 more authors
/ Abstract
Using angle-resolved photoemission spectroscopy, combined with first principle and coupled self-consistent Poisson-Schrödinger calculations, we demonstrate that potassium (K) atoms adsorbed on the low-temperature phase of 1$T$-TiSe$_2$ induce the creation of a two-dimensional electron gas (2DEG) and quantum confinement of its charge-density-wave (CDW) at the surface. By further changing the K coverage, we tune the carrier-density within the 2DEG that allows us to nullify, at the surface, the electronic energy gain due to exciton condensation in the CDW phase while preserving a long-range structural order. Our study constitutes a prime example of a controlled exciton-related many-body quantum state in reduced dimensionality by alkali-metal dosing.