Possible Electric-Field-Induced Superconducting States in Doped Silicene

TL;DR

This paper predicts that applying an electric field to doped silicene can induce a transition between different unconventional superconducting states, potentially enhancing the critical temperature and enabling experimental detection.

Contribution

It reveals a novel electric-field-induced quantum phase transition between singlet and triplet superconducting states in doped silicene, highlighting its potential for tunable superconductivity.

Findings

Electric field induces a transition from $d+id'$-wave to $f$-wave superconductivity.

Superconducting critical temperature is significantly enhanced by the electric field.

Proposes a dc SQUID experiment to detect the phase transition.

Abstract

Silicene has been synthesized recently, with experimental evidence showing possible superconductivity in the doped case. The noncoplanar low-buckled structure of this material inspires us to study the pairing symmetry of the doped system under a perpendicular external electric field. Our study reveals that the electric field induces an interesting quantum phase transition from the singlet chiral $d + id'$-wave superconducting phase to the triplet $f$-wave one. The emergence of the $f$-wave pairing results from the sublattice-symmetry-breaking caused by the electric field and the ferromagnetic-like intra-sublattice spin correlations at low dopings. Due to the enhanced density of states, the superconducting critical temperature of the system is enhanced by the electric field remarkably. Furthermore, we design a particular dc SQUID experiment to detect the quantum phase transition predicted here. Our results, if confirmed, will inject a new vitality to the familiar Si-based industry through adopting doped silicene as a tunable platform to study different types of exotic unconventional superconductivities.