Abstract
CoNb2O6 is a rare realization of the transverse-field Ising model, making it a useful tool for studying both equilibrium and nonequilibrium many-body quantum physics. Despite a large body of work dedicated to characterizing this material, details of the ordered states in the presence of relatively weak transverse fields have not been discussed in detail. Here, we present a detailed study of CoNb2O6 via ac susceptibility measurements in order to further characterize its low-temperature behavior in the presence of a transverse field. Specifically, we call attention to an unconventional freezing transition in zero field below TF=1.2 K, occurring within the well-known commensurate antiferromagnetic (CAFM) state that onsets at TN2=1.9 K. We performed a series of transverse-field quenches into this frozen state, which resulted in a slowly relaxing susceptibility, χ′(t), that followed a logarithmic decay within the time range measured. We discuss the frozen state in the context of the freezing of previously discussed “free” chains arising from domain walls between the four degenerate sublattices of the CAFM state. We also attempted to observe Kibble-Zurek scaling by quenching the transverse field into the frozen state at different rates. This produced a null result; the behavior can be fully explained by coarsening of domains over the time scale of the quenches. The absence of a clear Kibble-Zurek scaling is itself surprising, given the proposed ubiquity of the phenomenon for general second-order phase transitions.
Original language | English |
---|---|
Article number | 214424 |
Journal | Physical Review B |
Volume | 104 |
Issue number | 21 |
DOIs | |
State | Published - Dec 1 2021 |
Externally published | Yes |
Funding
This research was funded by Department of Energy Grant No. DE-SC0018972. The authors would like to acknowledge Professor Tarun Grover for insightful conversations relating to the Kibble-Zurek mechanism and domain coarsening effects. The authors would also like to thank Professor James Neilson for stimulating conversations about defect chemistry in crystalline materials. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by the National Science Foundation Cooperative Agreement No. DMR-1644779 and the state of Florida. Some figures were made using the 3D crystal modeling software vesta .