Ordered charge asphericity around dysprosium and structural deformation in DyB2C2

Area of Science:

• Condensed Matter Physics
• Materials Science
• Crystallography

Background:

• Dysprosium diboride carbide (DyB2C2) exhibits complex orbital ordering.
• Understanding the electronic and structural properties of ordered phases is crucial for materials science.

Purpose of the Study:

• To investigate the symmetry properties of the charge distribution in the orbitally ordered phase of DyB2C2.
• To determine the origin of the observed signals in nonresonant x-ray diffraction experiments.

Main Methods:

• Nonresonant x-ray diffraction using high-brilliance synchrotron radiation.
• Analysis of diffraction conditions to deduce symmetry properties.
• Quantitative inspection of experimental data.

Main Results:

• The symmetry of the charge distribution around dysprosium was determined at the quadrupolar level.
• Observed signals are not solely attributable to Dy 4f electrons.
• A distortion of the metaloid network accompanies the orbital ordering.

Conclusions:

• Orbital ordering in DyB2C2 involves coupled distortions of the metaloid network.
• The interplay between electronic and structural degrees of freedom governs the ordered phase.
• Further studies are needed to fully elucidate the microscopic mechanisms.