Hole dynamics in spin and orbital ordered vanadium perovskites

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid State Physics

Background:

• Doped perovskite vanadates exhibit complex spin and orbital ordering phenomena.
• Understanding the interplay between charge carriers and magnetic/orbital excitations is crucial for these materials.

Purpose of the Study:

• To develop a theoretical framework for doped perovskite vanadates with coupled spin and orbital orders.
• To investigate the renormalization of mobile holes by spin and orbital excitations.
• To explain the fragile spin-orbital order observed in specific vanadate compounds.

Main Methods:

• Theoretical modeling of mobile holes in a staggered t(2g) orbital array.
• Analysis of spin excitations (magnons) and orbital excitations (orbitons).
• Investigation of the relationship between spin order parameter and orbiton softening.

Main Results:

• Mobile holes are strongly renormalized by magnons in spin G-type and orbital C-type (SG-OC) order.
• Hole dynamics are significantly affected by orbitons in spin C-type and orbital G-type (SC-OG) order.
• The fragile SG-OC order in Y1-xCaxVO3 is linked to orbiton softening caused by a reduced spin order parameter.

Conclusions:

• The presented theory provides insights into the complex electronic behavior of doped perovskite vanadates.
• Spin and orbital excitations play a critical role in renormalizing charge carriers.
• Orbiton softening is identified as a key mechanism contributing to the instability of certain spin-orbital ordered phases.