Giant Oscillating Thermopower at Oxide Interfaces

Abstract

Understanding the nature of charge carriers at the LaAlO3/SrTiO3 interface is one of the major open issues in the full comprehension of the charge confinement phenomenon in oxide heterostructures. Here, we investigate thermopower to study the electronic structure in LaAlO3/SrTiO3 at low temperature as a function of gate field. In particular, under large negative gate voltage, corresponding to the strongly depleted charge density regime, thermopower displays record-high negative values of the order of 10^4 - 10^5 microV/K, oscillating at regular intervals as a function of the gate voltage. The huge thermopower magnitude can be attributed to the phonon-drag contribution, while the oscillations map the progressive depletion and the Fermi level descent across a dense array of localized states lying at the bottom of the Ti 3d conduction band. This study is the first direct evidence of a localized Anderson tail in the two-dimensional (2D) electron liquid at the LaAlO3/SrTiO3 interface.

Main text: 28 pages and 3 figures; Supplementary information: 29 pages, 5 figures and 1 table

References in corpus (26)

• Magnetic effects at the interface between nonmagnetic oxides
• Electric Field Control of the LaAlO${}_3$/SrTiO${}_3$ Interface Ground State
• Tunable Rashba spin-orbit interaction at oxide interfaces
• Direct imaging of the coexistence of ferromagnetism and superconductivity at the LaAlO3/SrTiO3 interface
• Coexistence of Magnetic Order and Two-dimensional Superconductivity at LaAlO${}_3$/SrTiO${}_3$ Interfaces
• Coexistence of superconductivity and ferromagnetism in two dimensions
• Dominant mobility modulation by the electric field effect at the LaAlO_3 / SrTiO_3 interface
• Two-dimensional quantum oscillations of the conductance at LaAlO3/SrTiO3 interfaces
• Large Thermoelectricity via Variable Range Hopping in Chemical Vapor Deposition Grown Single-layer MoS2
• Thermopower of a Kondo-correlated quantum dot
• Large capacitance enhancement and negative compressibility of two-dimensional electronic systems at LaAlO${}_3$/SrTiO${}_3$ interfaces
• Shubnikov-de Haas oscillations in SrTiO3\LaAlO3 interface
• Two-dimensional electron liquid state at LaAlO3-SrTiO3 interfaces
• Rashba induced magnetoconductance oscillations in the LaAlO3-SrTiO3 heterostructure
• Many-body large polaron optical conductivity in SrTi${}_{1-x}$Nb${}_x$O${}_3$
• Doping-dependent band structure of LaAlO${}_3$/SrTiO${}_3$ interfaces by soft x-ray polarization-controlled resonant angle-resolved photoemission
• Localized vs. delocalized character of charge carriers in LaAlO3/ SrTiO3 superlattices
• Seebeck effect in the conducting LaAlO_{3}/SrTiO_{3} interface
• Metal-Insulator Transition of the LaAlO3-SrTiO3 Interface Electron System
• Doping-induced dimensional crossover and thermopower burst in Nb-doped SrTiO${}_3$ superlattices
• Critical behaviour of thermopower and conductivity at the metal-insulator transition in high-mobility Si-MOSFETs
• Highly enhanced thermopower in two-dimensional electron systems at milliKelvin temperatures
• Electric-field-induced pyroelectric order and localization of the confined electrons in LaAlO3/SrTiO3 heterostructures
• The Conducting Channel at the LaAlO${}_3$/SrTiO${}_3$ Interface
• Evidence of Novel Quasiparticles in a Strongly Interacting Two-Dimensional Electron System: Giant Thermopower and Metallic Behaviour
• Density-dependent thermopower oscillations in mesoscopic two-dimensional electron gases

Cited by in corpus (17)

• Polaronic metal state at the LaAlO3/SrTiO3 interface
• Quantization of Hall Resistance at the Metallic Interface between an Oxide Insulator and SrTiO${}_3$
• Prediction of a native ferroelectric metal
• Tunable electron-electron interactions in LaAlO3/SrTiO3 nanostructures
• Design of $n$- and $p$-type oxide thermoelectrics in LaNiO${}_3$/SrTiO${}_3(001)$ superlattices exploiting interface polarity
• Controlling Kondo-like Scattering at the SrTiO3-based Interfaces
• Confinement- and strain-induced enhancement of thermoelectric properties in LaNiO${}_3$/LaAlO${}_3(001)$ superlattices
• Atomically precise lateral modulation of a two-dimensional electron liquid in anatase TiO2 thin films
• Inducing $n$- and $p$-type thermoelectricity in oxide superlattices by strain tuning of orbital-selective transport resonances
• Band-Order Anomaly at the γ-Al2O3/SrTiO3 Interface Drives the Electron-Mobility Boost
• From flexoelectricity to absolute deformation potentials: The case of SrTiO${}_3$
• Influence of the ferroelectric quantum critical point on SrTiO${}_3$ interfaces
• Large phonon-drag enhancement induced by narrow quantum confinement at the LaAlO3/SrTiO3 interface
• Enhancement of electron mobility at oxide interfaces induced by WO3 overlayers
• Chern insulating phases and thermoelectric properties of EuO/MgO(001) superlattices
• Ground state features and spectral properties of large polaron liquids from low to high charge densities
• Realizing Thermoelectric and Thermistor Bi-functionalities via Triggering Electron Correlations with Lattice-dipole