Electric Probe for the Toric Code Phase in Kitaev Materials through the Hyperfine Interaction.

Area of Science:

• Condensed Matter Physics
• Quantum Materials
• Spintronics

Background:

• The Kitaev model describes exotic spin liquid phases relevant to materials like iridates and alpha-ruthenium trichloride (α-RuCl3).
• Experimental evidence suggests a nematic transition to a gapped toric code phase in α-RuCl3, indicated by heat capacity measurements breaking C3 symmetry.

Purpose of the Study:

• To propose a novel mechanism for the electrical detection of the nematic transition in Kitaev spin liquids.
• To overcome the challenge that J_eff=1/2 spins lack an intrinsic electric quadrupole moment.

Main Methods:

• Theoretical proposal utilizing second-order perturbation theory.
• Investigating the emergence of a non-zero electric quadrupole moment (EQM) in virtual states.
• Linking the EQM to nuclear magnetic resonance (NMR) and Mössbauer spectroscopy.

Main Results:

• A mechanism is proposed where a magnetically induced EQM becomes detectable in the second-order perturbation.
• This EQM allows for the electrical detection of the nematic order parameter.
• The purely magnetic origin of this EQM distinguishes it from conventional electronic nematic phases.

Conclusions:

• The proposed method enables direct electrical detection of the nematic transition in Kitaev spin liquids.
• This facilitates the experimental verification of Kitaev's toric error-correction code realization in materials like α-RuCl3.
• Offers a new pathway to probe quantum phases of matter through electrical measurements.