Thermodynamics of the spin-1/2 two-leg ladder compound $(C_{5}H_{12}N)_{2} CuBr_{4}$

TL;DR

This paper investigates the thermodynamic properties of a spin-1/2 two-leg ladder compound under magnetic fields, revealing behaviors of entropy and specific heat, and their relation to quantum phase transitions.

Contribution

It provides combined numerical and analytical analysis of thermodynamic quantities in the compound, matching experimental observations and highlighting quantum critical effects.

Findings

Specific heat exhibits symmetric behavior around quantum critical fields.

Temperature drops near zero-temperature quantum phase transitions during adiabatic demagnetization.

Thermodynamic properties align with experimental results.

Abstract

The thermodynamic behavior of the spin $S=1/2$ antiferromagnetic two-leg ladder compound $(C_{5}H_{12}N)_{2} CuBr_{4}$ in a uniform magnetic field is studied using numerical and analytical approaches. The entropy $S(H,T)$ and specific heat $C(H,T)$ are calculated. The specific heat shows various behaviors in different regions of the magnetic field. The field-dependence of the specific heat is almost symmetric about the average of quantum critical fields in complete agreement with experimental results. In addition, it is found that during an adiabatic demagnetization process, temperature drops in the vicinity of the field induced zero-temperature quantum phase transitions.