Thermodynamics of frustrated spin lattices with flat bands

• Applicants: Professor Dr. Johannes Richter (†); Professor Dr. Jürgen Schnack
• Subject Area: Theoretical Condensed Matter Physics
• Term: from 2020 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 449703145

• Final Report Year: 2024

Final Report Abstract

Our project dealt with theoretical studies of magnetic properties of certain frustrated spin lattices such as the kagome as well as the square-kagomé lattice. Complementary to other studies we specialized on the behavior at non-zero temperatures and under applied magnetic fields. We obtained interesting (and internationally well-respected) results on the plateau structure of the magnetization as well as on thermal phenomena such as asymmetric melting of magnetization plateaus. We believe that this project was very successful. We could successfully address most of the questions we wanted, and we could open new doors that connect frustrated magnetism with the field of thermalization under unitary time evolution in closed systems.

Publications

• Accuracy of the typicality approach using Chebyshev polynomials. Zeitschrift für Naturforschung A, 76(9), 823-834.
  Schlüter, Henrik; Gayk, Florian; Schmidt, Heinz-Jürgen; Honecker, Andreas & Schnack, Jürgen
  
• Electric field driven flat bands: Enhanced magnetoelectric and electrocaloric effects in frustrated quantum magnets. Physical Review B, 105(5).
  Richter, Johannes; Ohanyan, Vadim; Schulenburg, Jörg & Schnack, Jürgen
  
• Frustrated magnetism of spin-1/2 Heisenberg diamond and octahedral chains as a statistical mechanical monomer-dimer problem. Physical Review B, 105(6).
  Strečka, Jozef; Verkholyak, Taras; Richter, Johannes; Karl'ová, Katarína; Derzhko, Oleg & Schnack, Jürgen
  
• Melting of Magnetization Plateaus for Kagomé and Square-Kagomé Lattice Antiferromagnets. Journal of the Physical Society of Japan, 91(9).
  Schlüter, Henrik; Richter, Johannes & Schnack, Jürgen
  
• Thermodynamics of the spin-half square kagome lattice antiferromagnet. Physical Review B, 105(14).
  Richter, Johannes; Derzhko, Oleg & Schnack, Jürgen
  
• Magnetism of the S=1/2 J1−J2 square-kagome lattice antiferromagnet. Physical Review B, 107(24).
  Richter, Johannes & Schnack, Jürgen
  
• Magneto- and barocaloric properties of the ferro-antiferromagnetic sawtooth chain. Zeitschrift für Naturforschung A, 79(3), 283-288.
  Reichert, Nico; Schlüter, Henrik; Heitmann, Tjark; Richter, Johannes; Rausch, Roman & Schnack, Jürgen
  
• Quantum spin spiral ground state of the ferrimagnetic sawtooth chain. SciPost Physics, 14(3).
  Rausch, Roman; Peschke, Matthias; Plorin, Cassian; Schnack, Jürgen & Karrasch, Christoph
  
• Thermodynamics of the S=12 maple-leaf Heisenberg antiferromagnet. Physical Review B, 112(10).
  Hutak, Taras