Physics

Prof. Ramesh Budhani
Indian Institute of Technology, Kanpur

The two-dimensional diffusive metal stabilized at the interface of SrTiO₃ and the Mott Insulator perovskite LaTiO₃^1-2 has challenged many notions related to the formation and electronic behavior of the two-dimensional electron gas (2DEG) at the well studies LaAlO₃-SrTiO₃ interface. Here we discuss specifically the stability of the superconducting phase³ at LaTiO₃ – SrTiO₃ interface, the nature of the superconductor – normal metal quantum phase transition (T=0 limit) driven by magnetic field, significance of the field vis-à-vis the Chandrasekhar - Clogston limit for depairing, and how the transition is initiated when the extent of Coulomb interaction amongst charge carriers is modulated by electrostatic gating⁴. The nature of the superconducting condensate is highlighted in the light of the Ti - t_2g orbital driven bands and their filling in the presence of a strong Rashba spin – orbit interaction (SOI). Towards the end of the talk, we will discuss the prominent effects of Rashba SOI on normal state quantum transport and how it renormalizes a Kondo-like electronic behavior in range of temperature T_c< T < 5K^5,6. The prominence of the Ti 3d⁰ and Ti 3d¹ correlated electron physics in these systems will be demonstrated further from our recent studies of 2DEG in ion irradiated SrTiO₃ crystals^7,8.

1. Advanced Materials 22, 4448(2010)                                                2. Phys. Rev. B 86, 075127(2012)

3. Nature Communications, 1, 89(2010)                                              4. Nature Materials 12, 542(2013)

5. Phys. Rev. B (Rapid Communication) 90, 081107(2014).6. Phys. Rev. B 90, 075133(2014)

7. Phys. Rev. B 91, 205117(2015) 8. Phys. Rev. B 92, 235115 (2015)