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Spin Qubit Based on Silicon Quantum Dots.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Spin Qubit Based on Silicon Quantum Dots./
Author:	Tariq, Bilal.
Description:	1 online resource (141 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 83-04, Section: B.
Contained By:	Dissertations Abstracts International83-04B.
Subject:	Physics. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28719374click for full text (PQDT)
ISBN:	9798460420735

Spin Qubit Based on Silicon Quantum Dots.
Tariq, Bilal.

Spin Qubit Based on Silicon Quantum Dots. - 1 online resource (141 pages)

Source: Dissertations Abstracts International, Volume: 83-04, Section: B.

Thesis (Ph.D.)--State University of New York at Buffalo, 2021.

Includes bibliographical references

The presence of degenerate conduction band valleys and how they are mixed by interfaces play critical roles in determining electron interaction and spectrum in a silicon nanostructure. In this thesis, we study the effect of interface steps on the magnitude and phase of valley-orbit coupling for an electron in a silicon quantum dot. Within the effective mass approximation, we find that the location of a step on the interface is important in determining both the magnitude and the phase of the valley-orbit coupling in a Si/SiGe quantum dot. Specifically, our numerical results show that the magnitude of valley orbit coupling can be suppressed up to 75% by a step of one atomic monolayer, and its phase can change by almost π. When two steps are present, the minimum value of the valley-orbit coupling can even approach zero. We also clarify the effects of an applied external magnetic field and the higher orbital states on the valley-orbit coupling. We then investigate how the valley phases affect the exchange interaction in a symmetric two-electron silicon double quantum dot. Through a configuration interaction calculation, we find that exchange splitting is suppressed at a finite value of valley phase difference between the two dots and reaches its minimum value (∼ 0) when the phase difference is π. Such a suppression can be explained using the Hubbard model, through the valley-phase-dependent dressing by the doubly occupied states on the ground singlet and triplet states. The contributions of the higher orbital states also play a vital role in determining the value of the exchange energy in general, which is a crucial parameter for applications such as exchange gates for spin qubits.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798460420735Subjects--Topical Terms:

516296
Physics.
Subjects--Index Terms:

Spin qubitIndex Terms--Genre/Form:

542853
Electronic books.

Spin Qubit Based on Silicon Quantum Dots.
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245 1 0 $a Spin Qubit Based on Silicon Quantum Dots.
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300 $a 1 online resource (141 pages)
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500 $a Source: Dissertations Abstracts International, Volume: 83-04, Section: B.
500 $a Advisor: Hu, Xuedong.
502 $a Thesis (Ph.D.)--State University of New York at Buffalo, 2021.
504 $a Includes bibliographical references
520 $a The presence of degenerate conduction band valleys and how they are mixed by interfaces play critical roles in determining electron interaction and spectrum in a silicon nanostructure. In this thesis, we study the effect of interface steps on the magnitude and phase of valley-orbit coupling for an electron in a silicon quantum dot. Within the effective mass approximation, we find that the location of a step on the interface is important in determining both the magnitude and the phase of the valley-orbit coupling in a Si/SiGe quantum dot. Specifically, our numerical results show that the magnitude of valley orbit coupling can be suppressed up to 75% by a step of one atomic monolayer, and its phase can change by almost π. When two steps are present, the minimum value of the valley-orbit coupling can even approach zero. We also clarify the effects of an applied external magnetic field and the higher orbital states on the valley-orbit coupling. We then investigate how the valley phases affect the exchange interaction in a symmetric two-electron silicon double quantum dot. Through a configuration interaction calculation, we find that exchange splitting is suppressed at a finite value of valley phase difference between the two dots and reaches its minimum value (∼ 0) when the phase difference is π. Such a suppression can be explained using the Hubbard model, through the valley-phase-dependent dressing by the doubly occupied states on the ground singlet and triplet states. The contributions of the higher orbital states also play a vital role in determining the value of the exchange energy in general, which is a crucial parameter for applications such as exchange gates for spin qubits.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2023
538 $a Mode of access: World Wide Web
650 4 $a Physics. $3 516296
650 4 $a Quantum physics. $3 726746
650 4 $a Atomic physics. $3 3173870
653 $a Spin qubit
653 $a Silicon
653 $a Quantum dots
655 7 $a Electronic books. $2 lcsh $3 542853
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690 $a 0599
690 $a 0748
710 2 $a ProQuest Information and Learning Co. $3 783688
710 2 $a State University of New York at Buffalo. $b Physics. $3 1025831
773 0 $t Dissertations Abstracts International $g 83-04B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28719374 $z click for full text (PQDT)