Heat Transport in Spin Chains with Weak Spin-Phonon Coupling.

Area of Science:

• Condensed Matter Physics
• Quantum Materials Science

Background:

• Strontium cuprates like Sr(2)CuO(3) and SrCuO(2) are key materials for studying quantum magnetism.
• Understanding heat transport in these S=1/2 Heisenberg spin chains is crucial for their technological applications.

Purpose of the Study:

• To theoretically investigate heat transport in S=1/2 large-J Heisenberg spin chains.
• To develop a microscopic model for spin-phonon interactions and their effect on thermal conductivity.

Main Methods:

• Utilizing bosonization techniques to describe spin excitations.
• Analyzing multiboson processes to derive spin-phonon scattering rates.
• Comparing theoretical predictions with experimental data for strontium cuprates.

Main Results:

• A microscopic spin-phonon scattering rate was derived, explaining phonons as thermal defects for spin excitations.
• The derived mean-free path shows a distinctive temperature dependence, characteristic of critical spin chains.
• The model successfully describes experimental observations without invoking large spin-phonon coupling constants.

Conclusions:

• The proposed model offers a more natural explanation for heat transport in cuprates compared to previous theories.
• It avoids the need for large coupling constants, which would imply a spin-Peierls transition not observed in these materials.