Flatland
Reading as

Vanadium and chromium dichalcogenides

MX₂ (M = V, Cr; X = S, Se, Te)

Also called VSe₂, VS₂, VTe₂, CrTe₂, CrSe₂

van der Waals crystal depends on form

A cautionary tale for 2D magnetism, followed by a success. In 2018 single layers of vanadium diselenide were reported to be ferromagnetic above room temperature, which would have been a breakthrough; later spectroscopy found no magnetic order in clean layers, only a charge-density wave, and where the original signal came from is still discussed. Chromium ditelluride delivered what VSe2 had promised: bulk crystals are ferromagnetic up to about 310 K, thin flakes stay magnetic at room temperature, and thin CrSe2 grown on WSe2 is magnetic and unchanged after months in air.

Crystal structure

  • Se
  • V
Cell
Hexagonal, a = 3.35 Å
Atoms per cell
3
V–Se bond
2.47 Å
Height
3.07 Å between the outer atom centres
Vanadium in edge-sharing octahedra of selenium, the 1T arrangement shared by TiSe2 and the other members of this family. Bulk VSe2 is a metal with a charge-density wave. Early reports that single layers stay ferromagnetic at room temperature have been disputed by later measurements, and the question of what the magnetism of a monolayer actually is remains open. One layer of bulk 1T-VSe2 (Hoschek, Zeitschrift für anorganische und allgemeine Chemie 242, 49, 1939; COD 1538289): a = 3.36 Å, selenium planes 1.53 Å above and below the V plane.

Key properties

  • Bulk 1T-VSe2 is a metal with a 4×4×3 charge-density wave; monolayers form a different √3×√7 charge order, with gaps opening below ~140 K
  • Room-temperature ferromagnetism reported in VSe2 monolayers in 2018 has not been confirmed: ARPES and X-ray magnetic circular dichroism find no ferromagnetic order in pristine layers
  • 1T-CrTe2: an itinerant ferromagnet with a bulk Curie temperature of ~310 K and in-plane moments; flakes about 20 nm thick stay ferromagnetic at room temperature
  • In CVD-grown CrTe2 the Curie temperature rises as crystals thin from ~130 nm to ~8 nm, and the easy axis turns from in-plane to out-of-plane
  • Monolayer CrTe2 grown on a substrate has been found to be antiferromagnetic, unlike the bulk
  • CrSe2 grown on WSe2 down to the monolayer is ferromagnetic and stable in air for months; VS2 and VTe2 monolayers also form charge-density waves

How it is made

  • Molecular beam epitaxy of VSe2, VTe2 and CrTe2 monolayers and films
  • Removal of potassium from KCrTe2 to make bulk 1T-CrTe2, followed by exfoliation
  • Chemical vapour deposition of CrTe2, and van der Waals epitaxy of CrSe2 on WSe2
  • Exfoliation of metallic VS2 into nanosheets for electrodes

Uses, and how close they are

  • Room-temperature 2D ferromagnets for spintronic devices (CrTe2)lab
  • Metallic electrodes for supercapacitors and batteries (VS2, VSe2)lab

Readiness runs lab → prototype → pilot → deployed.

Open problems

  1. Where did the room-temperature magnetic signal of the 2018 VSe2 monolayers come from – defects, the substrate, or a state that is hard to reproduce?
  2. Why does monolayer CrTe2 turn antiferromagnetic while the bulk is ferromagnetic, and how much do the substrate and strain decide it?
  3. Can chromium self-intercalation, which turns CrTe2 into Cr1+δTe2, be controlled well enough to set the magnetism layer by layer?

Going deeper

Short notes for specialists. Choose a lens in the header and yours comes first.

For theoreticians · your lens

Metallic 1T layers with competing instabilities. In VSe2, calculations find a √3×√7 charge-ordered state close in energy to a ferromagnetic 1×1 state, so strain, doping or the choice of exchange–correlation functional can flip the answer. CrTe2 magnetism is itinerant and sensitive to the Cr–Te–Cr bond angle and to self-intercalated chromium, which DFT+U treats very differently depending on U; monolayer ground states need noncollinear and spin-spiral calculations.

For experimentalists · your lens

Back magnetism claims with a local probe – X-ray magnetic circular dichroism, spin-polarised STM or NV magnetometry – as well as transport, and rule out magnetic impurities and oxidation; the VSe2 story shows how easily extrinsic signals appear. Check the stoichiometry of CrTe2, because extra chromium in the gap changes both the anisotropy and the Curie temperature. Cap MBE monolayers with Se or Te before they leave vacuum.

For engineers · your lens

CrTe2 is one of the few van der Waals ferromagnets that work at room temperature, and CVD growth already exists; composition control and wafer-scale uniformity will decide whether it reaches spintronic devices. The vanadium compounds are better suited to electrochemical electrodes than to magnetism.

In the research tracks

Theory frontiers

Growth methods

Recent news

The newest items tagged VSe2, CrTe2, CrSe2, from the news feed updated 5 Oct 2026.

Preprintnot yet peer reviewed arXiv

Modulation of charge density waves in a twisted vortex moire superlattice

Twisted moire superlattices in van-der-Waals heterostructures provide a powerful platform for engineering correlated states through moire-band reconstruction. However, whether globally coherent electronic orders can be continuously manipulated at the nanoscale remains largely unexplored. Reconstructed moire structures…

TheoryExperimentVSe₂, CrTe₂, CrSe₂NbSe₂, NbS₂, NbTe₂
Preprintnot yet peer reviewed arXiv

Many-body electronic structure, self-doped double-exchange, and Hund metallicity in 1T-CrTe2 bulk and monolayer

The van der Waals (vdW) ferromagnet 1T-CrTe2 is an emerging spintronics platform, notable for its high Curie temperature (Tc) and intriguing transport properties. However, the fundamental interplay between the electron correlations and magnetism underlying its high Tc still remains elusive. Here, using density…

TheoryVSe₂, CrTe₂, CrSe₂

All 11 items tagged VSe₂, CrTe₂, CrSe₂ in the news feed  ·  RSS feed for VSe₂, CrTe₂, CrSe₂

Key references

  1. Metallic few-layered VS2 ultrathin nanosheets: high two-dimensional conductivity for in-plane supercapacitorsFeng et al. · Journal of the American Chemical Society 133, 17832 (2011)cited by 1,143doi:10.1021/ja207176c
  2. Ferromagnetism in layered metastable 1T-CrTe2Freitas et al. · Journal of Physics: Condensed Matter 27, 176002 (2015)cited by 188doi:10.1088/0953-8984/27/17/176002
  3. Strong room-temperature ferromagnetism in VSe2 monolayers on van der Waals substratesBonilla et al. · Nature Nanotechnology 13, 289 (2018)cited by 1,713doi:10.1038/s41565-018-0063-9
  4. Evidence of spin frustration in a vanadium diselenide monolayer magnetWong et al. · Advanced Materials 31, 1901185 (2019)cited by 153doi:10.1002/adma.201901185
  5. Anomalous thickness dependence of Curie temperature in air-stable two-dimensional ferromagnetic 1T-CrTe2 grown by chemical vapor depositionMeng et al. · Nature Communications 12, 809 (2021)cited by 381doi:10.1038/s41467-021-21072-z
  6. Van der Waals epitaxial growth of air-stable CrSe2 nanosheets with thickness-tunable magnetic orderLi et al. · Nature Materials 20, 818 (2021)cited by 360doi:10.1038/s41563-021-00927-2
Transition metal dichalcogenides TiSe₂, ZrSe₂, HfSe₂ Titanium, zirconium and hafnium dichalcogenides van der Waals crystal
type
depends on form
thickness
~0.57–0.66 nm per layer
band gap
0.5–1.2 eV
most mature
prototype
Lithium and sodium battery electrodes (TiS2) 2D magnets Fe₃GeTe₂, Fe₃GaTe₂ Iron germanium and gallium tellurides van der Waals crystal
type
magnet
thickness
~0.8 nm per Fe₃GeTe₂ layer
band gap
none
most mature
lab
All-van-der-Waals magnetic tunnel junctions and spin–orbit torque devices 2D magnets CrI₃, VI₃, TiCl₃ Transition-metal trihalides van der Waals crystal
type
magnet
thickness
~0.6–0.7 nm per layer
band gap
1.2–2 eV
most mature
lab
Spin-filter tunnel junctions and magnetic memory concepts Transition metal dichalcogenides TaS₂, TaSe₂ Tantalum disulfide and diselenide van der Waals crystal
type
depends on form
thickness
~0.6 nm per layer
most mature
lab
Ultrafast memristive switches and oscillators