Rb2Cu2Mo3O12

Chemical formula:

Rb_2-2xCs_2xCu₂(MoO₄)₃

Lattice type:

Monoclinic

How to grow:

Bridgman furnace

Magnetic model:

S=1/2 frustrated chain

Why is it cool:

Frustrated quantum spin chain materials and unique quantum multiferroics.

Growing single cystals of copper molybdenum oxides is extremly challenging, and growing them large is seemingly impossible. Nonetheless, some single crystal specimen were successfully synthesized in our group.

The complicated structure of copper molybdenum oxides can be viwed as composed of spin chains with competing ferro- and antiferromagnetic interactions. While the Rb material is a quantum paramagnet and has a single field-induced ordered phase, the Cs counterpart orders already at zero field and has a rather complex magnetic phase diagram.

Both compounds are quantum multiferroics: electrical polarization is linearly coupled to the magnetic order parameter. This allows one to study magnetic quantum criticality through dielectric measurements, accessing quantities that are usually impossible to measure. In addition, the Cs system shows a new type of dielectric relaxation mediated by quantum-critical magnons.

Cs2Cu2Mo3O12 phase diagram — Phase diagram of Cs₂Cu₂Mo₃O₁₂ in differently applied magnetic fields obtained by means of specific heat measurements and torque magnetometry.

D. Flavián, P. A. Volkov, S. Hayashida, K. Yu. Povarov, S. Gvasaliya, P.
S. Hayashida, D. Blosser, K. Yu. Povarov, Z. Yan, S. Gvasaliya, A. N.
Ponomaryov, S. A. Zvyagin, and A. Zheludev, Chandra, A. Zheludev,
Dielectric relaxation in the quantum multiferroics Rb2Cu2Mo3O12 and
Cs2Cu2Mo3O12, external page Phys. Rev. B 110, 174433 (2024)

D. Flavián, Pavel A. Volkov, S. Hayashida, K. Yu. Povarov, S. Gvasaliya, Premala Chandra, and A. Zheludev, Dielectric Relaxation by Quantum Critical Magnons, external page Phys. Rev. Lett. 130, 216501 (2023).

S. Hayashida, L. Huberich, D. Flavián, Z. Yan, K. Yu. Povarov, S.
Gvasaliya, A. Zheludev, Critical dielectric susceptibility at a magnetic
BEC quantum critical point, external page Phys. Rev. Research 3, 033053 (2021).

D. Flavián, S. Hayashida, L. Huberich, D. Blosser, K. Yu. Povarov, Z. Yan, S. Gvasaliya, A. Zheludev, Magnetic phase diagram of the linear quantum ferro-antiferromagnet Cs2Cu2Mo3O12 , external page Phys. Rev. B 101, 224408 (2020)

S. Hayashida, D. Blosser, K. Yu. Povarov, Z. Yan, S. Gvasaliya, A. N. Ponomaryov, S. A. Zvyagin, and A. Zheludev, One- and three-dimensional quantum phase transitions and anisotropy in Rb₂Cu₂Mo₃O₁₂, external page Phys. Rev. B 100, 134427 (2019).