Nonlinear Hall effect and multichannel conduction inLaTiO3/SrTiO3superlattices

Abstract

We report magneto-transport properties of heterointerfaces between the Mott insulator LaTiO 3 and the band insulator SrTiO 3 in a delta-doping geometry. At low temperatures, we have found a strong nonlinearity in the magnetic field dependence of the Hall resistivity, which can be effectively controlled by varying the temperature and the electric field. We attribute this effect to multichannel conduction of interfacial charges generated by an electronic reconstruction. In particular, the formation of a highly mobile conduction channel revealed by our data is explained by the greatly increased dielectric permeability of SrTiO 3 at low temperatures, and its electric-field dependence reflects the spatial distribution of the quasi-two-dimensional electron gas.

Electrostatic carrier doping of GdTiO3/SrTiO3 interfaces

“…Compensating mobile electrons are easily accessible for RTiO 3 /SrTiO 3 structures, as can be visualized by considering the atomically sharp interface as a 50:50 mixture of RTiO 3 and SrTiO 3 , which has the required free electron density [20]. Transport and optical measurements of LaTiO 3 /SrTiO 3 interfaces reveal densities close to those expected for electronic reconstruction [16,21], but interpretation is complicated by conduction by non-interfacial carriers from both substrates and films [15,16]; LaTiO 3 films reported in the literature are often metallic [22]. The sheet resistances of GdTiO 3 grown directly on LSAT and of GdTiO 3 grown on SrTiO 3 buffer layers with different thicknesses are shown in Fig.…”

“…While too resistive for meaningful Hall measurements, the Seebeck coefficient was measured and is positive (ptype), as found for stoichiometric GdTiO 3 [23]. All bilayers are n-type and metallic if the was linear and n-type down to the lowest temperatures [29], in contrast to LaTiO 3 /SrTiO 3 [15,16]. All of the electrons contributing to the Hall resistance satisfy μB << 1 .…”

“…To date, attention has focused on LaAlO 3 /SrTiO 3 and LaTiO 3 /SrTiO 3 interfaces grown by pulsed laser deposition [1,[14][15][16].…”

Two-dimensional electron gas in a modulation-doped SrTiO3/Sr(Ti, Zr)O3 heterostructure

“…[3][4][5][6][7] Most studies thus far have focused on 2DEGs at polar/nonpolar interfaces, such as LaAlO 3 / SrTiO 3,[8][9][10] LaTiO 3 /SrTiO 3,11,12 and GdTiO 3 /SrTiO 3.…”

Symmetry‐Driven Atomic Rearrangement at a Brownmillerite–Perovskite Interface

“…Examples include the discovery of a 2-dimensional electron gas (2DEG) and thermopower enhancement in LaTiO 3 /SrTiO 3 (STO) heterostructures [1][2][3] , electric-field control of spin polarization between ferroelectric and ferromagnetic film layers [4] and colossal ionic conductivity at the yttria-stabilized ZrO 2 (YSZ)/STO interface [5] . The strong property modification in heterostructures such as these suggests that the structural, electronic, lattice and orbital degrees of freedom at the interface can be tuned from the individual constituents.…”