Spin-dependent processes at the crystalline Si-SiO_2 interface at high magnetic fields

TL;DR

This study investigates spin-dependent charge carrier transitions at the Si-SiO2 interface under high magnetic fields using EDMR, revealing new tunneling processes relevant for quantum computing readout mechanisms.

Contribution

It provides experimental evidence of spin-dependent tunneling between identical states at high magnetic fields, supporting Kane's proposal for donor qubit readout.

Findings

Spin-dependent tunneling between P_b states observed at high magnetic fields.

Decoupling of 31P and P_b resonance responses at high fields.

New spin-dependent processes dominate over low-field recombination mechanisms.

Abstract

An experimental study on the nature of spin-dependent excess charge carrier transitions at the interface between (111) oriented phosphorous doped ([P] ~ 10^15 cm^3) crystalline silicon and silicon dioxide at high magnetic field (B_0 ~ 8.5 T) is presented. Electrically detected magnetic resonance (EDMR) spectra of the hyperfine split 31P donor electron transitions and paramagnetic interface defects were conducted at temperatures in the range 3 K < T < 12 K. The results at these previously unattained (for EDMR) magnetic field strengths reveal the dominance of spin-dependent processes that differ from the previously well investigated recombination between the 31P donor and the P_b state, which dominates at low magnetic fields. While magnetic resonant current responses due to 31P and P_b states are still present, they do not correlate and only the P_b contribution can be associated with an interface process due to spin-dependent tunneling between energetically and physically adjacent P_b states. This work provides an experimental demonstration of spin-dependent tunneling between physically adjacent and identical electronic states as proposed by Kane for readout of donor qubits.