We report electronic transport measurements through a silicon hybrid double quantum dot consisting of a donor and a quantum dot. Transport spectra show resonant tunneling peaks involving different valley states, which illustrate the valley splitting in a quantum dot on a Si/SiO2 interface. The detailed gate bias dependence of double dot transport allows a first direct observation of the valley splitting in the quantum dot, which is controllable between 160-240 ueV with an electric field dependence 1.2 +- 0.2 meV/(MV/m). A large valley splitting is an essential requirement to implement a physical electron spin qubit in a silicon quantum dot.
@article{arxiv.1604.04020,
title = {Resonant tunneling spectroscopy of valley eigenstates on a hybrid double quantum dot},
author = {T. Kobayashi and J. van der Heijden and M. G. House and S. J. Hile and Pablo Asshoff and M. F. Gonzalez-Zalba and M. Vinet and M. Y. Simmons and S. Rogge},
journal= {arXiv preprint arXiv:1604.04020},
year = {2016}
}