1. University Grenoble Alpes, F-38000 Grenoble, France and CEA, LETI, MINATEC Campus, F-38054 Grenoble, France
2. University Grenoble Alpes, F-38000 Grenoble, France and CEA, INAC, MINATEC Campus, F-38054 Grenoble, France
3. IBM Microelectronics, 2070 Route 52, Hopewell Junction, New York 12533, USA
4. IBM Research, 257 Fuller Road, Albany, New York 12203, USA