Field-tuned ferroquadrupolar quantum phase transition in the insulator TmVO₄

Area of Science:

• Condensed Matter Physics
• Quantum Materials
• Magnetism and Magnetic Materials

Background:

• Electronic nematicity in insulators is a complex phenomenon driven by local electronic degrees of freedom.
• Understanding the role of crystal lattice and quantum fluctuations is crucial for characterizing phase transitions.

Purpose of the Study:

• Investigate the ferroquadrupolar phase transition in TmVO₄.
• Explore the tuning of this transition to a quantum critical point using magnetic fields.
• Analyze deviations from semiclassical models to understand quantum effects.

Main Methods:

• Low-temperature heat-capacity measurements
• Magnetocaloric-effect measurements
• Neutron-diffraction studies
• Analysis using the transverse-field Ising model

Main Results:

• TmVO₄ exhibits a continuous ferroquadrupolar phase transition driven by 4f orbitals.
• The transition can be tuned to a quantum critical point by an in-plane magnetic field.
• Deviations from semiclassical mean-field behavior at higher fields indicate quantum fluctuations.
• Crystal lattice interactions and coupling to phonons significantly influence critical behavior.

Conclusions:

• TmVO₄ serves as a model material for studying quantum criticality in insulators.
• Electronic nematicity provides a paradigm for understanding quantum critical phenomena.
• The interplay between local electronic degrees of freedom and the crystal lattice is key.