Dielectric properties of sputteredSrTiO3films

Abstract

The dielectric properties of (100)-oriented epitaxial SrTiOs films as used in high-T, heterostructures have been studied as a function of temperature and applied electric field by using in situ grown heterostructures (Mg/SrTiOs/SrTiOs. Nb and Au/YBasCusOq /SrTiOs/SrTiOs. Nb). The dielectric behavior of these films is characterized by a rather low sample capacitance as compared to bulk single-crystal values and by occurrences of maxima in the capacitance-voltage and capacitancetemperature curves. The maximum attainable polarization was found to be 80 mC/m at 4.2 K. Complementary measurements on single crystals of SrTi03 and SrTi03.Nb reveal that the behavior of these SrTi03 thin Blms can be understood from the bulk properties with additional strong charge trapping at the film-substrate interface.

Electric field control of the LaAlO3/SrTiO3 interface ground state

“…It is known that charge trapping in SrTiO 3 can occur and may cause the appearance of hysteresis in the C(V ) measurements [19]. Indeed the capacitance was found to depend on the voltage sweep history.…”

Electrostatic modulation of anisotropic magnetotransport in Ar+-irradiated SrTiO3: Effects of boundary scattering

“…Due to proximity to a ferroelectric instability, the dielectric constant ǫ of STO diverges at low temperatures, reaching as high as ∼ 24000ǫ 0 . 26 The increase in ǫ can give rise to a decrease in the confinement of carriers near the interface, particularly for LAO/STO samples that have sheet carrier densities less than 6×10 13 cm −2 . 4,27 On the premise the negative MR measured in low R s LAO/STO samples arises from a loss in boundary scattering, 10 analysis using our methodology 16 indicates the Q2DEG thickness in these samples is ≥ 50 nm.…”

Enhancing the electron mobility via delta-doping in SrTiO3

“…1(a)). However, the dielectric constant of SrTiO 3 6 is known to be strongly suppressed by moderate electric fields, 12 which reflects the incipient ferroelectric character of SrTiO 3 . 23 Therefore, the observed narrow carrier confinement can be ascribed to the electric field produced by the charged impurities, together with the suppressed dielectric constant, as suggested by subband calculations.…”

“…11 Although the transport properties can be tuned using the electrostatic field effect, the carrier distribution is concurrently altered, which is accelerated by the electric-field dependent dielectric constant of SrTiO 3 . [12][13][14] To draw fully on the potential of these fascinating materials, both the carrier concentration and distribution must be independently well controlled to a degree approaching the levels of current semiconductor technology, which has developed thanks to longstanding efforts to improve the growth and doping techniques of thin films. 15 In the case of SrTiO 3 , the growth of high-quality, uniformly doped, thin films has recently been reported.…”