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D. D. Osheroff

Publications and source records attributed to D. D. Osheroff.

4 recordsLinked to original sources
arXiv2003

Field-induced structural aging in glasses at ultra low temperatures

In non-equilibrium experiments on the glasses Mylar and BK7, we measured the excess dielectric response after the temporary application of a strong electric bias field at mK--temperatures. A model recently developed describes the observed long time decays qualitatively for Mylar [PRL 90, 105501, S. Ludwig, P. Nalbach, D. Rosenberg, D. Osheroff], but fails for BK7. In contrast, our results on both samples can be described by including an additional mechanism to the mentioned model with temperature independent decay times of the excess dielectric response. As the origin of this novel process beyond the "tunneling model" we suggest bias field induced structural rearrangements of "tunneling states" that decay by quantum mechanical tunneling.

cond-mat.dis-nn↗
arXiv2003

Memory effects in Amorphous Solids below 20 mK

At temperatures below 1 K, the capacitance of a glass sample changes due to the application of a DC field in accordance with A. Burins dipole gap theory. However, we now report that below 20 mK, during the first sweep cycle of the DC electric field the capacitance is smaller by about $10^{-5}$ compared to any subsequent sweep. Despite this overall shift the field dependence follows the dipole gap predictions. In a subsequent sweep to higher DC fields the dielectric constant drops by about $10^{-5}$ as soon as the applied field is higher than any field previously applied. A picture involving the dynamics of resonant pairs provides a qualitative description of this behavior.

cond-mat↗
arXiv1998

Evidence for growth of collective excitations in glasses at low temperatures

We present new data on the nonequilibrium acoustic response of glasses to an applied dc electric field below 1K. When compared with the analogous dielectric response of the same material, the acoustic data show, within experimental precision, identical dependence on the perturbing field, but stronger temperature dependence. These data are difficult to reconcile with simple generalizations of the dipole gap model of two-level system (TLS) dielectric response, unless we assume that as T is decreased, interaction-based TLS collective effects increase.

cond-mat.dis-nn↗