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Controlling the Charge Density Wave Transition in Monolayer TiSe 2 : Substrate and Doping Effects
Author(s) -
Kolekar Sadhu,
Bonilla Manuel,
Diaz Horacio Coy,
Hashimoto Makato,
Lu Donghui,
Batzill Matthias
Publication year - 2018
Publication title -
advanced quantum technologies
Language(s) - English
Resource type - Journals
ISSN - 2511-9044
DOI - 10.1002/qute.201800070
Subject(s) - monolayer , van der waals force , doping , materials science , highly oriented pyrolytic graphite , condensed matter physics , charge density wave , substrate (aquarium) , photoemission spectroscopy , x ray photoelectron spectroscopy , nanotechnology , superconductivity , chemistry , physics , scanning tunneling microscope , nuclear magnetic resonance , oceanography , molecule , geology , organic chemistry
TiSe 2 is an exciting material because it can be tuned between superconducting and charge density wave (CDW) transitions. In the monolayer limit, TiSe 2 exhibits a sizable energy gap in the CDW phase that makes it a promising quantum material. It is shown that interfacing a single layer of TiSe 2 with dissimilar van der Waals materials enables control of its properties. Using angle‐resolved photoemission spectroscopy, the energy gap opening is analyzed as a function of temperature for TiSe 2 monolayers supported on different van der Waals substrates. A substantial increase in the CDW transition temperature of ≈45 K is observed on MoS 2 compared to graphite (highly oriented pyrolytic graphite) substrates. This control of the CDW in monolayer TiSe 2 is suggested to arise from varying charge screening of the unconventional CDW of TiSe 2 by the substrate. In addition, the suppression of CDW order and a complete closing of the energy gap by electron doping of monolayer TiSe 2 is demonstrated. Regulating the many‐body physics phenomena in monolayer TiSe 2 lays the foundation of modifying TiSe 2 in, for example, artificial van der Waals heterostructures and thus creates a new approach for utilizing the quantum states of TiSe 2 in device applications.