Coexistence of Unidirectional Charge Density Waves in LaTe_(3)

The classic rare-earth tritelluride provides an ideal platform to study the strong correlation state owing to its stable structures and abundance of orders.Here we report the observation of an undiscovered charge density wave(CDW)in LaTe_(3)under 4.2 K,the transition temperature of the CDW states is fitted to be 35 K,and confirmed by the evanishment of this CDW at 77 K via using temperature-dependent scanning tunneling microscope/spectroscopy.The coexistence of these CDWs is confirmed by the atomic resolution and beating pattern simulation.It is the first time to observe the coexistence of unidirectional charge density waves system,providing a new platform to understand the competition and evolution between strong correlation states,and get a deeper sight into the phase lag between different order parameters.

MgO intercalation and crystallization between epitaxial graphene and Ru(0001)

Graphene on insulator is the foundation of its practical applications in electronic information technology.However,fabrication of graphene on insulating substrates suffers from small size and limited quality by direct growth of graphene on dielectric substrates,and the method of transferring graphene onto insulating substrates is not so compatible with the large-scale production in industry.Here,we report the fabrication of high-quality,large-area,single-crystal graphene on crystalline magnesium oxide(MgO),which has a dielectric constant of 7–10.Magnesium and oxygen are intercalated at the interface of epitaxial graphene/Ru(0001)and form crystalline structure after high-temperature annealing.The graphene/MgO/Ru(0001)sample was characterized by low energy electron diffraction(LEED),scanning tunneling microscopy(STM),X-ray photoelectron spectroscopy(XPS),and scanning transmission electron microscopy(STEM).LEED pattern shows that the magnesium oxide displays crystalline structure,and STM studies show clearly that the top layer is graphene.STEM characterization of as-intercalated sample demonstrates that the MgO intercalation layer,with a thickness of up to 2.3 nm,has a crystal structure of rock salt MgO,and the out-of-plane crystal orientation is[001].Our work provides a new route for fabrication of graphene on high dielectric constant insulators,which may have potential applications in future electronics.