Spin qubits based on shallow donors in silicon are a promising quantum information technology with enormous potential scalability due to the existence of robust silicon-processing infrastructure.However,the most accur...Spin qubits based on shallow donors in silicon are a promising quantum information technology with enormous potential scalability due to the existence of robust silicon-processing infrastructure.However,the most accurate theories of donor electronic structure lack predictive power because of their reliance on empirical fitting parameters,while predictive ab initio methods have so far been lacking in accuracy due to size of the donor wavefunction compared to typical simulation cells.We show that density functional theory with hybrid and traditional functionals working in tandem can bridge this gap.Our first-principles approach allows remarkable accuracy in binding energies(67 meV for bismuth and 54 meV for arsenic)without the use of empirical fitting.We also obtain reasonable hyperfine parameters(1263 MHz for Bi and 133 MHz for As)and superhyperfine parameters.We demonstrate the importance of a predictive model by showing that hydrostatic strain has much larger effect on the hyperfine structure than predicted by effective mass theory,and by elucidating the underlying mechanisms through symmetry analysis of the shallow donor charge density.展开更多
基金This work was supported in part by the UC Santa Barbara Quantum Foundry through the National Science Foundation“Quantum Materials Science,Engineering and Information(Q-AMASE-i)”program,Award#DMR-1906325M.W.S.’s work on superhyperfine parameters and exchange splitting was supported by an American Society for Engineering Education(ASEE)fellowship at the US Naval Research Laboratory+3 种基金Use was made of computational facilities purchased with funds from NSF(CNS-1725797)and administered by the Center for Scientific Computing(CSC)The CSC is supported by the California NanoSystems Institute and the Materials Research Science and Engineering Center(NSF DMR-1720256)at UC Santa BarbaraThis work also used the Extreme Science and Engineering Discovery Environment(XSEDE),which is supported by NSF grant number ACI-1548562the National Energy Research Scientific Computing Center,a DOE Office of Science User Facility supported by the Office of Science of the U.S.Department of Energy under Contract No.DE-AC02-05CH11231.
文摘Spin qubits based on shallow donors in silicon are a promising quantum information technology with enormous potential scalability due to the existence of robust silicon-processing infrastructure.However,the most accurate theories of donor electronic structure lack predictive power because of their reliance on empirical fitting parameters,while predictive ab initio methods have so far been lacking in accuracy due to size of the donor wavefunction compared to typical simulation cells.We show that density functional theory with hybrid and traditional functionals working in tandem can bridge this gap.Our first-principles approach allows remarkable accuracy in binding energies(67 meV for bismuth and 54 meV for arsenic)without the use of empirical fitting.We also obtain reasonable hyperfine parameters(1263 MHz for Bi and 133 MHz for As)and superhyperfine parameters.We demonstrate the importance of a predictive model by showing that hydrostatic strain has much larger effect on the hyperfine structure than predicted by effective mass theory,and by elucidating the underlying mechanisms through symmetry analysis of the shallow donor charge density.
