## Robust semi-Dirac points and unconventional topological phase transitions in doped superconducting Sr2IrO4 tunnel coupled to t2g electron systems

Mats Horsdal, Timo Hyart

SciPost Phys. 3, 041 (2017) · published 22 December 2017

- doi: 10.21468/SciPostPhys.3.6.041
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### Abstract

Semi-Dirac fermions are known to exist at the critical points of topological phase transitions requiring fine-tuning of the parameters. We show that robust semi-Dirac points can appear in a heterostructure consisting of superconducting Sr2IrO4 and a t2g electron system (t2g-ES) without fine-tuning. They are topologically stable in the presence of the symmetries of the model, metallic t2g-ES and a single active band in Sr2IrO4. If the t2g metal is coupled to two different layers of Sr2IrO4 (effectively a multiband superconductor) in a three-layer-structure the semi-Dirac points can split into two stable Dirac points with opposite chiralities. A similar transition can be achieved if the t2g-ES supports intrinsic triplet superconductivity. By considering Sr2RuO4 as an example of a t2g-ES we predict a rich topological phase diagram as a function of various parameters.

### Cited by 3

### Ontology / Topics

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^{1 }Mats Horsdal, -
^{2 }Timo Hyart

^{1}Universitetet i Oslo / University of Oslo [UiO]^{2}Jyväskylän yliopisto / University of Jyväskylä