Identification of Strong and Weak Interacting Two-Level Systems in KBr:CN

Abstract

Tunneling two-level systems (TLSs) are believed to be the source of phenomena such as the universal low temperature properties in disordered and amorphous solids, and 1/f noise. The existence of these phenomena in a large variety of dissimilar physical systems testifies for the universal nature of the TLSs, which however, is not yet known. Following a recent suggestion that attributes the low temperature TLSs to inversion pairs [M. Schechter and P. C. E. Stamp, arXiv:0910.1283.] we calculate explicitly the TLS-phonon coupling of inversion symmetric and asymmetric TLSs in a given disordered crystal. Our work (a)estimates parameters that support the theory in M. Schechter and P. C. E. Stamp, arXiv:0910.1283, in its general form, and (b)positively identifies, for the first time, the relevant TLSs in a given system.