We consider a deformable spin-1/2 antiferromagnetic XXZ Heisenberg chain and examine the spin-chain lattice compressibility as well as the sound velocity as a function of an external magnetic field applied either along the z axis or along the x axis. For strong fields, we observe a noticeable increase (with jump and hysteresis) of the lattice compressibility. Our findings are obtained by several complimentary approaches (Jordan-Wigner fermionization method, exact diagonalizations, and density matrix renormalization group technique). The lattice compressibility is related to the sound velocity which is accessible in acoustic experiments.
by Oleg Derzhko
Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, L’viv Ukraine
at SA1A1 (P1 lecture hall) Institute of Physics, Park Angelinum 9, Košice, P. J. Šafárik University
on Thursday December 13, 2018