Thermodynamic Functions of Terbium Hafnate

The molar heat capacity of terbium hafnate with a pyrochlore structure was measured by relaxation and adiabatic calorimetry. The smoothed values of the molar heat capacity were used to calculate the thermodynamic functions in the temperature range 6–330 K. The general form of the Schottky anomaly was determined.

Thermodynamics of General Heisenberg Spin Tetramers Composed of Coupled Quantum Dimers

Advances in quantum computing technology have been made in recent years due to the evolution of spin clusters. Recent studies have tended towards spin cluster subgeometries to understand more complex structures better. These molecular magnets provide a multitude of phenomena via exchange interactions that allow for advancements in spintronics and other magnetic system applications due to the possibility of increasing speed, data storage, memory, and stability of quantum computing systems. Using the Heisenberg spin–spin exchange Hamiltonian and exact diagonalization, we examine the evolution of quantum energy levels and thermodynamic properties for various spin configurations and exchange interactions. The XXYY quantum spin tetramer considered in this study consists of two coupled dimers with exchange interactions α1J and α1′J and a dimer–dimer exchange interaction α2J. By varying spin values and interaction strengths, we determine the exact energy eigenstates that are used to determine closed-form analytic solutions for the heat capacity and magnetic susceptibility of the system and further analyze the evolution of the properties of the system based on the parameter values chosen. Furthermore, this study shows that the Schottky anomaly shifts towards zero as the ground-state of the system approaches a quantum phase transition between spin states. Additionally, we investigate the development of phase transitions produced by the convergence of the Schottky anomaly with both variable exchange interactions and external magnetic field.

Electric field and charged impurity doping effects on the Schottky anomaly of $\beta_{12}$-borophene

Due to the coexistence of Dirac and triplet fermions, monolayer $\beta_{12}$-borophene has recently attracted both experimental and theoretical researchers. In particular, various phase transitions have been recently reported in the...