Supplementary Information 1 Control of the millisecond spin lifetime of an electrically probed atom 2 3 4

1 Supplementary Information 1 Control of the millisecond spin lifetime of an electrically probed atom 2 3 4 William Paul1, Kai Yang1,2, Susanne Baumann1,3, Niklas Romming4, Taeyoung Choi1, 5 Christopher P. Lutz1, and Andreas J. Heinrich1,5 6 1 IBM Research Division, Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA. 7 2 School of Physical Sciences and Key Laboratory of Vacuum Physics, University of Chinese Academy of 8 Sciences, Beijing 100049, China. 9 3 Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland. 10 4 Department of Physics, University of Hamburg, 20355 Hamburg, Germany. 11 5 Physics Department, Ewha Womans University, Seoul, Republic of Korea (present address). 12 13 14 15 Table of contents 16 17 18 1. Relaxation rates.......................................................................................................................................... 2 19 1.1 Relaxation by inelastic electron scattering ................................................................................ 2 20 1.2 Tunnel barrier transmission factors ............................................................................................. 3 21 1.3 Quantum states and inelastic scattering probability ............................................................. 5 22 1.4 Layer-dependence of quantum states and transition intensities ..................................... 8 23 1.5 Rates with applied bias voltage ................................................................................................... 11 24 2. Temperature dependence ................................................................................................................... 15 25 3. Point contact conductance with different tips ........................................................................... 16 26 4. Lifetime on multi-layer MgO .............................................................................................................. 17 27 4.1 Inelastic electron scattering applied to multi-layer films ................................................. 17 28 4.2 Additional non-electronic rate ..................................................................................................... 19 29 4.3 Lifetime at B = 2 T.............................................................................................................................. 20 30 5. Magnetic field orientation and T1 vs B saturation ................................................................... 22 31 6. STM topography ...................................................................................................................................... 23 32 7. Thickness of MgO films ........................................................................................................................ 24 33 7.1 Point contact conductance of Fe atoms on 1-4 ML MgO films ........................................ 25 34 7.2 STM topography of 1 and 2 ML MgO films .............................................................................. 26 35 7.3 dz/dV of 1 and 2 ML MgO films .................................................................................................... 27 36 8. References ................................................................................................................................................. 29 37 Control of the millisecond spin lifetime of an electrically probed atom