Misfit Layer Compounds: A Platform for Heavily Doped 2D Transition Metal Dichalcogenides
Raphaël Leriche, Alexandra Palacio‐Morales, Marco Campetella, Cesare Tresca, Shunsuke Sasaki, Christophe Brun, François Debontridder, Pascal David, Imad Arfaoui, O. Šofranko, Tomáš Samuely, Geoffroy Kremer, Claude Monney, T. Jaouen, Laurent Cario, Matteo Calandra, Tristan Cren
Abstract
Abstract Transition metal dichalcogenides (TMDs) display a rich variety of instabilities such as spin and charge orders, Ising superconductivity, and topological properties. Their physical properties can be controlled by doping in electric double‐layer field‐effect transistors (FET). However, for the case of single layer NbSe 2 , FET doping is limited to ≈ 1 × 10 14 cm −2 , while a somewhat larger charge injection can be obtained via deposition of K atoms. Here, by performing angle‐resolved photoemission spectroscopy, scanning tunneling microscopy, quasiparticle interference measurements, and first‐principles calculations it is shown that a misfit compound formed by sandwiching NbSe 2 and LaSe layers behaves as a NbSe 2 single layer with a rigid doping of 0.55–0.6 electrons per Nb atom or ≈ 6 × 10 14 cm −2 . Due to this huge doping, the 3 × 3 charge density wave is replaced by a 2 × 2 order with very short coherence length. As a tremendous number of different misfit compounds can be obtained by sandwiching TMDs layers with rock salt or other layers, this work paves the way to the exploration of heavily doped 2D TMDs over an unprecedented wide range of doping.