Dielectric relaxation phenomena in smoky quartz

Tunneling phenomena of trapped holes in ZnO: Li

“…Since the asymmetry of the potential wells is large, we can assume d=kTb1, as in the case of the O À -Al 3+ hole center in SiO 2 . There the tunneling splitting G is very small, only of the order of 10 À3 -10 À4 meV (5-10 mK) [7]. In this approximation t ph becomes temperature independent.…”

“…[6,7]). The total transition probability is given by the sum of the transition probabilities of all different path ways.…”

“…This points to tunneling transitions via a high-lying intermediate state at Energy E n . According to Sussmann's theory [6,7] the expression for the transition probability or, equivalently, relaxation time has the same form as in the case of simple thermal transitions over the potential barrier:…”

Shallow traps and radiative recombination processes inLu3Al5O12:Cesingle crystal scintillator

“…26 Thermally assisted tunneling processes were also considered in low temperature dielectric losses of crystalline quartz. 27 Qualitatively, one can propose a simple model limited to a single couple of electron and hole trapping sites at a specific distance r, see inset of Fig. 8.…”

Dielectric Relaxation in Smoky Quartz at Very Low Temperatures

“…The energy splitting of these TLS is given by E = C/O: + A2 where A, is the tunnel splitting and A the asymmetry caused by random electric fields. A is broadly distributed, the dielectric results above 1 K [2] and specific heat results . The dipole moments P are apparent values (in Debye), without taking into account the local field correction [3, 71, the angle 0 = 60" between P a n d the C-axis has been discussed in [3].…”