Unconventional bipartite entanglement in the quantum dimer magnet Yb<sub>2</sub>Be<sub>2</sub>SiO<sub>7</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41881986.
- Also identified by DOI 10.1038/s41467-026-69258-7 and PMC identifier 13018291.
- Licence recorded as CC BY.
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Abstract
The quantum dimer magnet, with antiferromagnetic intradimer and interdimer Heisenberg exchange between spin-1/2 moments, is known to host an <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>(</mo> <mrow> <mfenced><mrow><mi>↑</mi> <mi>↓</mi></mrow> </mfenced> <mo>-</mo> <mfenced><mrow><mi>↓</mi> <mi>↑</mi></mrow> </mfenced> </mrow> <mo>)</mo></mrow> <mo>/</mo> <msqrt><mrow><mn>2</mn></mrow> </msqrt> </math> singlet ground state when the intradimer exchange is dominant. Rare-earth-based quantum dimer systems with strong spin-orbit coupling offer the opportunity for tuning their magnetic properties by using magnetic anisotropy as a control knob. Here, we present bulk characterization and neutron scattering measurements of the quantum dimer magnet Yb<sub>2</sub>Be<sub>2</sub>SiO<sub>7</sub>. We find that the Yb<sup>3+</sup> ions can be described by an effective spin-1/2 model at low temperatures and the system does not show signs of magnetic order down to 50 mK. The magnetization, heat capacity, and neutron spectroscopy data can be well-described by an isolated dimer model with highly anisotropic exchange that stabilizes a singlet ground state with a wavefunction <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>(</mo> <mrow> <mfenced><mrow><mi>↑</mi> <mi>↑</mi></mrow> </mfenced> <mo>-</mo> <mfenced><mrow><mi>↓</mi> <mi>↓</mi></mrow> </mfenced> </mrow> <mo>)</mo></mrow> <mo>/</mo> <msqrt><mrow><mn>2</mn></mrow> </msqrt> </math> or <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>(</mo> <mrow> <mfenced><mrow><mi>↑</mi> <mi>↑</mi></mrow> </mfenced> <mo>+</mo> <mfenced><mrow><mi>↓</mi> <mi>↓</mi></mrow> </mfenced> </mrow> <mo>)</mo></mrow> <mo>/</mo> <msqrt><mrow><mn>2</mn></mrow> </msqrt> </math> . Our results show that strong spin-orbit coupling can induce unusual entangled states of matter in quantum dimer magnets.