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Title: Valley dependent anisotropic spin splitting in silicon quantum dots

Spin qubits hosted in silicon (Si) quantum dots (QD) are attractive due to their exceptionally long coherence times and compatibility with the silicon transistor platform. To achieve electrical control of spins for qubit scalability, recent experiments have utilized gradient magnetic fields from integrated micro-magnets to produce an extrinsic coupling between spin and charge, thereby electrically driving electron spin resonance (ESR). However, spins in silicon QDs experience a complex interplay between spin, charge, and valley degrees of freedom, influenced by the atomic scale details of the confining interface. We report experimental observation of a valley dependent anisotropic spin splitting in a Si QD with an integrated micro-magnet and an external magnetic field. We show by atomistic calculations that the spin-orbit interaction (SOI), which is often ignored in bulk silicon, plays a major role in the measured anisotropy. Moreover, inhomogeneities such as interface steps strongly affect the spin splittings and their valley dependence. This atomic-scale understanding of the intrinsic and extrinsic factors controlling the valley dependent spin properties is a key requirement for successful manipulation of quantum information in Si QDs.
Authors:
ORCiD logo [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [4] ;  [4] ;  [4] ; ORCiD logo [4] ;  [4] ;  [2] ; ORCiD logo [1]
  1. Purdue Univ., West Lafayette, IN (United States). Electrical and Computer Engineering and Network for Computational Nanotechnology
  2. Delft Univ. of Technology (Netherlands). QuTech and Kavli Inst. of Nanoscience
  3. Delft Univ. of Technology (Netherlands). QuTech and Kavli Inst. of Nanoscience; AGH - Univ. of Science and Technology, Krakow (Poland). Academic Centre for Materials and Nanotechnology
  4. Univ. of Wisconsin, Madison, WI (United States)
Publication Date:
Grant/Contract Number:
FG02-03ER46028; W911NF-12-0607; DMR-1121288; EEC-0228390
Type:
Accepted Manuscript
Journal Name:
npj Quantum Information
Additional Journal Information:
Journal Volume: 4; Journal Issue: 1; Journal ID: ISSN 2056-6387
Publisher:
Nature Partner Journals
Research Org:
Univ. of Wisconsin, Madison, WI (United States). Materials Research Science and Engineering Center (MRSEC)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); US Army Research Office (ARO); National Science Foundation (NSF); European Research Council (ERC)
Contributing Orgs:
Purdue Univ., West Lafayette, IN (United States). Network for Computational Nanotechnology (nanoHUB.org)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; 97 MATHEMATICS AND COMPUTING
OSTI Identifier:
1460097