Two-dimensional electron gases at LaAlO3/SrTiO3 interfaces: orbital symmetry and hierarchy engineered by crystal orientation

D Pesquera; M Scigaj; P Gargiani; A Barla; J Herrero-Martín; E Pellegrin; S M Valvidares; J Gázquez; M Varela; N Dix; J Fontcuberta; F Sánchez; G Herranz

doi:10.1103/PhysRevLett.113.156802

Two-dimensional electron gases at LaAlO3/SrTiO3 interfaces: orbital symmetry and hierarchy engineered by crystal orientation

Phys Rev Lett. 2014 Oct 10;113(15):156802. doi: 10.1103/PhysRevLett.113.156802. Epub 2014 Oct 7.

Authors

D Pesquera¹, M Scigaj², P Gargiani³, A Barla⁴, J Herrero-Martín³, E Pellegrin³, S M Valvidares³, J Gázquez¹, M Varela⁵, N Dix¹, J Fontcuberta¹, F Sánchez¹, G Herranz¹

Affiliations

¹ Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, Bellaterra E-08193, Catalonia, Spain.
² Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, Bellaterra E-08193, Catalonia, Spain and Departamento de Física, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Catalonia, Spain.
³ ALBA Synchrotron Light Source, Carretera BP 1413 km 3.3, E-08290 Cerdanyola del Vallès, Barcelona, Spain.
⁴ Istituto di Struttura della Materia, ISM CNR, Area Science Park Basovizza (Ts), Trieste I-34149, Italy.
⁵ Departamento Física Aplicada III, Universidad Complutense de Madrid, Madrid, 28040 Spain and Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.

PMID: 25375731
DOI: 10.1103/PhysRevLett.113.156802

Abstract

Recent findings show the emergence of two-dimensional electron gases (2DEGs) at LaAlO(3)/SrTiO(3) interfaces along different orientations; yet details on band reconstructions have remained so far unknown. Via x-ray linear dichroism spectroscopy, we demonstrate that crystal symmetry imposes distinctive 2DEG orbital hierarchies on (001)-and (110)-oriented quantum wells, allowing selective occupancy of states of different symmetry. Such orientational tuning expands the possibilities for electronic engineering of 2DEGs and opens up enticing opportunities to understand the link between orbital symmetry and complex correlated states at LaAlO(3)/SrTiO(3) quantum wells.