Specific heat of segmented Heisenberg quantum spin chains in (Yb_{1-x}Lu_x)_4As_3

Abstract

We report low-temperature specific heat, $C(T)$, measurements on (Yb${}_{1-x}$Lu${}_x$)${}_4$As${}_3$ with $x=0.01$ and $x=0.03$, where nonmagnetic Lu atoms are randomly distributed on antiferromagnetic $S=1/2$ Heisenberg chains with $J/k_{\mathrm{B}}=28$ K. The observed reduction of $C$ below 15 K with increasing $x$ is accurately described by quantum transfer matrix simulations without any adjustable parameter, implying that the system is an excellent experimental realization of segmented quantum spin chains. Finite-size effects consistent with conformal-field theory predictions are leading to the formation of an effective low-energy gap. The size of the gap increases with Lu content and accounts for the impurity driven reduction of the specific heat. For both concentrations our results verify experimentally the low temperature scaling behavior established theoretically and also confirm the value of $J$ determined from pure Yb${}_4$As${}_3$.

7 pages, 6 figures

References in corpus (2)

• Chain breaks and the susceptibility of Sr_2Cu_{1-x}Pd_xO_{3+δ} and other doped quasi one-dimensional antiferromagnets
• Thermodynamics of impurities in the anisotropic Heisenberg spin-1/2 chain

Cited by in corpus (3)

• $\text{Ab Initio}$ Theory of the Impact from Grain Boundaries and Substitutional Defects on Superconducting Nb${}_3$Sn
• Bose glass behavior in (Yb${}_{1-x}$Lu${}_x$)${}_4$As${}_3$ representing the randomly diluted quantum spin-1/2 chains
• Magnetic properties of an antiferromagnetic spin-1/2 XYZ model in the presence of different magnetic fields: finite-size effects of inhomogeneity property