Year: 2017
Type: article
Abstract: Due to the nonlinear dielectric response within ${\mathrm{SrTiO}}_{3}$ (STO), an accumulation layer created by positive charges at the surface of the STO sample ($x=0$) has an electron density profile $n(x)$ that slowly decays as $1/{x}^{12/7}$. Here we show that the long tail of $n(x)$ causes the magnetization and the specific heat of the accumulation layer to diverge at large $x$. We explore the truncation of the tail by the finite sample width $W$, the transition from the nonlinear to linear dielectric response with dielectric constant $\ensuremath{\kappa}$, and the use of a back gate with a negative voltage $\ensuremath{-}\left|V\right|$. We find that both the magnetization and specific heat are anomalously large and obey nontrivial power law dependences on $W, \ensuremath{\kappa}$, or $\left|V\right|$. We conclude with a discussion of how the capacitance as a function of the back gate voltage may be used to study the shape of the $n(x)$ tail in thin samples.
Authors: Michael Sammon, Han Fu, B. I. Shklovskii
Institution: University of Minnesota
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Funder: University of Minnesota
OpenAlex ID: W2622344490