Synthesis and Properties of Monolayer MnSe with Unusual Atomic Structure and Antiferromagnetic Ordering.

Markus Aapro,Héctor González Herrero,Somesh C Ganguli,Md Nurul Huda,Jeyakumar Karthikeyan,Peter Liljeroth,Xin Huang,Shawulienu Kezilebieke,Hannu-Pekka Komsa

doi:10.1021/acsnano.1c05532

Markus Aapro, Héctor González Herrero + Show 7 more

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https://doi.org/10.1021/acsnano.1c05532

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Journal: ACS nano	Publication Date: Jul 27, 2021
Citations: 30	License type: CC BY 4.0

Affiliation: Aalto University, University of Oulu

Abstract

Transition metal chalcogenides (TMCs) are a large family of 2D materials that are currently attracting intense interest. TMCs with 3d transition metals provide opportunities for introducing magnetism and strong correlations into the material with manganese standing out as a particularly attractive option due to its large magnetic moment. Here we report on the successful synthesis of monolayer manganese selenide on a NbSe2 substrate. Using scanning tunneling microscopy and spectroscopy experiments and global structure prediction calculations at the density functional theory level, we identify the atomic structure and magnetic and electronic properties of the layered Mn2Se2 phase. The structure is similar to the layered bulk phase of CuI or a buckled bilayer of h-BN. Interestingly, our results suggest that the monolayer is antiferromagnetic, but with an unusual out-of-plane ordering that results in two ferromagnetic planes.

Highlights

Transition metal chalcogenides (TMCs) are an important and large family of 2D materials with the most famous members belonging to the transition metal dichalcogenides
Using scanning tunneling microscopy (STM) and spectroscopy (STS) experiments and global structure prediction calculations at the density functional theory (DFT) level, we identify the material to possess an unusual atomic structure similar to that found in the layered bulk phase of CuI
Layers with a similar structure can be found in bulk β-CuI,[37] but, on the basis of our database and literature searches, we found no synthesized or exfoliated 2D materials with this structure

Summary

Introduction

Transition metal chalcogenides (TMCs) are an important and large family of 2D materials with the most famous members belonging to the transition metal dichalcogenides (e.g., the prototypical MoS2). Monochalcogenides (such as FeSe and GaSe) and trichalcogenides (such as TiS3) have been widely studied. These materials host a broad variety of different kinds of physical phenomena such as valley physics, strong excitonic effects, superconductivity, charge-density wave (CDW) states, and topological phases of matter.[1−4]. Several layered 3d-TMCs have been experimentally synthesized, such as TiX2 (X = S, Se, or Te), TNiiXT3e,2.V5−X123, CrTe2, Out of. Ferromagnetic ground states have been computationally predicted for VSe2, CrTe2, and MnSe2,14,15 but experimentally the situation is still far from clear. As for VSe2, there are several reports indicating either the presence or the lack of ferromagnetism.[16−19]

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