Epitaxy

Engineering

Chemical physics

Materials science

Layer (electronics)

Economics

Molecule

Chemical engineering

Physics

Nanotechnology

Organic chemistry

van der Waals force

Condensed matter physics

Chemistry

Finance

Optoelectronics

Order (exchange)

Nature Materials

The discovery of intrinsic ferromagnetism in ultrathin two-dimensional van der Waals crystals opens up exciting prospects for exploring magnetism in the ultimate two-dimensional limit. Here, we show that environmentally stable CrSe2 nanosheets can be readily grown on a dangling-bond-free WSe2 substrate with systematically tunable thickness down to the monolayer limit. These CrSe2/WSe2 heterostructures display high-quality van der Waals interfaces with well-resolved moiré superlattices and ferromagnetic behaviour. We find no apparent change in surface roughness or magnetic properties after months of exposure in air. Our calculations suggest that charge transfer from the WSe2 substrate and interlayer coupling within CrSe2 play a critical role in the magnetic order in few-layer CrSe2 nanosheets. The highly controllable growth of environmentally stable CrSe2 nanosheets with tunable thickness defines a robust two-dimensional magnet for fundamental studies and potential applications in magnetoelectronic and spintronic devices. CrSe2 nanosheets grown on WSe2 show no apparent change in surface roughness or magnetic properties after months of exposure in air. Calculations suggest that charge transfer from the WSe2 substrate and interlayer coupling within CrSe2 play a critical role.

Van der Waals epitaxial growth of air-stable CrSe2 nanosheets with thickness-tunable magnetic order