Electrically Tunable Optical Switching of a Mott Insulator–Band Insulator Interface

Abstract

The electrical conductivity of the two‐dimensional (2D) electron gas at the interface of epitaxially grown ultrathin films of LaTiO3 on SrTiO3 shows a large gain upon near‐UV excitation. The gain in conductivity can be turned on or off by the application of a gate voltage of correct polarity. This feature of the 2D gas should allow realization of optoelectronic devices whose functionality can be enhanced by sequential application of an electric field and light.

Dynamics of photogenerated nonequilibrium electronic states inAr+-ion-irradiatedSrTiO3

“…Recently, Rastogi et al, have studied the photoconductivity (PC) in LaAlO 3 /SrTiO 3 and LaTiO 3 /SrTiO 3 based heterostructures, [23][24][25][26] where they found persistent photoconductivity (PPC) and suggested a role of oxygen vacancies, 24,25 created in STO during the film deposition, in the stability of the PPC. These exciting results have increased interest in the studies of oxygen deficient STO even more.…”

Defect-induced photoluminescence of strontium titanate and its modulation by electrostatic gating

“…[4][5][6] The properties of STO can be varied from insulating to semiconducting 7 , metallic 8 and even superconducting at low temperatures 9,10 on electron doping. Recently, it has been demonstrated that the interfaces of STO with perovskite oxides like LaAlO 3 and LaTiO 3 can stabilize a two dimensional electron gas (2DEG) with mobilities as high as ∼10 4 cm 2 /V s. 6,11,12 However, a 2DEG can also be formed on the surface of bare STO either by electrostatic gating or by Ar + -ion irradiation. 13 The later creates oxygen vacancies on the surface of STO, which make it metallic.…”

Magneto-transport in LaTi1−xMnxO3/SrTiO3 oxide heterostructures

“…Artificially tailored oxide films on the (001) oriented SrTiO 3 single crystal substrate show novel opto-electronic properties at the interface due to the formation of a quasi two dimensional electron gas 1,2 (q-2DEG) having electron concentration of ≈ 10 13 cm -2 and mobility of the order ≈ 10 4 cm 2 /Vs. Proposed mechanisms for formation of (q-2DEG) are electronic reconstruction (polar catastrophe) 1,3 atomic reconstruction 4 , inter-site mixing of elements 4 and oxygen vacancy during growth 5 .…”

“…In these systems, one of the extensively studied systems is LaAlO 3 [LAO] deposited on TiO 2 terminated SrTiO 3 [STO] (001). Another very interesting system is the interface of 3d transition metal oxide LaTiO 3 [LTO]/SrTiO 3 [STO] which also exhibits (q-2DEG) at the interface and goes to superconducting state at 260 mK 2,8 . So, both LTO and LAO films, which are prototype of Mott and band insulators respectively, show the characteristic property of electron confined conductivity at the interface, while other 3d transition metals like LaMnO 3 (LMO) and LaCrO 3 (LCO) do not.…”