Ce doping in T-La2CuO4 films: Broken electron-hole symmetry for high-Tc superconductivity

TL;DR

This study demonstrates successful Ce doping in T-La2CuO4 films via molecular beam epitaxy, revealing broken electron-hole symmetry and contrasting effects on superconductivity compared to Nd2CuO4-based compounds.

Contribution

First successful Ce incorporation into T-La2CuO4 films up to x ~ 0.06, showing distinct electronic behavior and symmetry breaking not observed in bulk synthesis.

Findings

Ce doping increases resistivity, making the material more insulating.

Electron-hole symmetry is broken in T-phase La2CuO4-based materials.

Ce doping does not induce superconductivity in T-La2CuO4.

Abstract

We attempted Ce doping in La2CuO4 with the K2NiF4 (T) structure by molecular beam epitaxy. At low growth temperature and with an appropriate substrate choice, we found that Ce can be incorporated into the K2NiF4 lattice up to x ~ 0.06, which had not yet been realized in bulk synthesis. The doping of Ce makes T-La2-xCexCuO4 more insulating, which is in sharp contrast to Ce doping in La2CuO4 with the Nd2CuO4 structure, which makes the compounds superconducting. The observed smooth increase in resistivity from hole-doped side (T-La2-xSrxCuO4) to electron-doped side (T-La2-xCexCuO4) indicates that electron-hole symmetry is broken in the T-phase materials.