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Effect of electric field on spin splitting in SiGe quantum wells (QWs) has been studied theoretically. Microscopical calculations of valley and spin splittings are performed in the effective $sp^3d^5s^*$ tight-binding model. The splittings…

Mesoscale and Nanoscale Physics · Physics 2008-10-07 M. O. Nestoklon , E. L. Ivchenko , J. -M. Jancu , P. Voisin

Electrons confined in Si quantum dots possess orbital, spin, and valley degrees of freedom (d.o.f.). We perform Landau-Zener-Stuckelberg-Majorana (LZSM) interferometry on a Si double quantum dot that is strongly coupled to a microwave…

Mesoscale and Nanoscale Physics · Physics 2018-10-17 X. Mi , S. Kohler , J. R. Petta

We report direct measurements of the valley susceptibility, the change of valley population in response to applied symmetry-breaking strain, in an AlAs two-dimensional electron system. As the two-dimensional density is reduced, the valley…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 O. Gunawan , Y. P. Shkolnikov , K. Vakili , T. Gokmen , E. P. De Poortere , M. Shayegan

We test the valley-filtering capabilities of a quantum dot inscribed by locally straining an $\alpha$-$\mathcal{T}_3$ lattice. Specifically, we consider an out-of-plane Gaussian bump in the center of a four-terminal configuration and…

Mesoscale and Nanoscale Physics · Physics 2021-04-16 Alexander Filusch , Alan R. Bishop , Avadh Saxena , Gerhard Wellein , Holger Fehske

Strain is extensively used to controllably tailor the electronic properties of materials. In the context of indirect band-gap semiconductors such as silicon, strain lifts the valley degeneracy of the six conduction band minima, and by…

In this paper, we studied the inter-valley interactions between the orbital functions associated with multi-valley of silicon (Si) quantum dots. Numerical calculations show that the inter-valley coupling between orbital functions increases…

Quantum Physics · Physics 2009-11-10 Doyeol Ahn

We have investigated the valley splitting of two-dimensional electrons in high quality Si/Si$_{1-x}$Ge$_x$ heterostructures under tilted magnetic fields. For all the samples in our study, the valley splitting at filling factor $\nu=3$…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 K. Lai , T. M. Lu , W. Pan , D. C. Tsui , S. Lyon , J. Liu , Y. H. Xie , M. Muhlberger , F. Schaffler

Research on Si quantum dot spin qubits is motivated by the long spin coherence times measured in Si, yet the orbital spectrum of Si dots is increased as a result of the valley degree of freedom. The valley degeneracy may be lifted by the…

Mesoscale and Nanoscale Physics · Physics 2015-05-18 Dimitrie Culcer , Lukasz Cywinski , Qiuzi Li , Xuedong Hu , S. Das Sarma

This work investigates the feasibility of electrical valley filtering for holes in transition metal dichalcogenides. We look specifically into the scheme that utilizes a potential barrier to produce valley-dependent tunneling rates, and…

Mesoscale and Nanoscale Physics · Physics 2020-05-12 Tzu-Chi Hsieh , Mei-Yin Chou , Yu-Shu Wu

We report on the valley blockade and the multielectron Kondo effect generated by an impurity atom in a silicon nano field effect device. According to the spin-valley nature of tunnelling processes, and consistently with those allowed by the…

Mesoscale and Nanoscale Physics · Physics 2015-09-10 A. Crippa , M. L. V. Tagliaferri , D. Rotta , M. De Michielis , G. Mazzeo , M. Fanciulli , R. Wacquez , M. Vinet , E. Prati

In solid, the crystalline structure can endow electron an internal degree of freedom known as valley, which characterizes the degenerate energy minima in momentum space. The recent success in optical pumping of valley polarization in 2D…

Mesoscale and Nanoscale Physics · Physics 2017-03-07 Xing-Tao An , Jiang Xiao , M. W. -Y. Tu , Hongyi Yu , Vladimir I. Fal'ko , Wang Yao

Proposed silicon-based quantum-computer architectures have attracted attention because of their promise for scalability and their potential for synergetically utilizing the available resources associated with the existing Si technology…

Materials Science · Physics 2009-11-10 Belita Koiller , R. B. Capaz , X. Hu , S. Das Sarma

In monolayers of transition metal dichalcogenides the nonlocal nature of the effective dielectric screening leads to large binding energies of excitons. Additional lateral confinement gives rise to exciton localization in quantum dots. By…

Mesoscale and Nanoscale Physics · Physics 2021-03-16 Anvar S. Baimuratov , Alexander Högele

Silicon/silicon-germanium heterostructures have many important advantages for hosting spin qubits. However, controlling the valley splitting (the energy splitting between the two low-lying conduction-band valleys) remains a critical…

Mesoscale and Nanoscale Physics · Physics 2024-01-12 Merritt P. Losert , M. A. Eriksson , Robert Joynt , Rajib Rahman , Giordano Scappucci , Susan N. Coppersmith , Mark Friesen

Tunneling transport across the p-n-p junction of Weyl semimetal with tilted energy dispersion is investigated. We report that the electrons around different valleys experience opposite direction refractions at the barrier interface when the…

Mesoscale and Nanoscale Physics · Physics 2018-02-12 Can Yesilyurt , Zhuo Bin Siu , Seng Ghee Tan , Gengchiau Liang , Shengyuan A. Yang , Mansoor B. A. Jalil

Off-resonance conductance through weakly coupled quantum dots ("valley conductance") is governed by cotunneling processes in which a large number of dot states participate. Virtually the same states participate in the transport at…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Reinhard Baltin , Yuval Gefen

Interactions between electrons can strongly affect the shape and functionality of multi-electron quantum dots. The resulting charge distributions can be localized, as in the case of Wigner molecules, with consequences for the energy…

Mesoscale and Nanoscale Physics · Physics 2021-12-14 H. Ekmel Ercan , S. N. Coppersmith , Mark Friesen

Spin and valley-orbit splittings are calculated in SiGe/Si/SiGe quantum wells (QWs) by using the tight-binding approach. In accordance with the symmetry considerations an existence of spin splitting of electronic states in perfect QWs with…

Mesoscale and Nanoscale Physics · Physics 2008-10-07 M. O. Nestoklon , L. E. Golub , E. L. Ivchenko

Valley Hall effect is an appearance of the valley current in the direction transverse to the electric current. We develop the microscopic theory of the valley Hall effect in two-dimensional semiconductors where the electrons are dragged by…

Mesoscale and Nanoscale Physics · Physics 2020-10-14 M. M. Glazov , L. E. Golub

A valley degree of freedom (DOF) in transition metal dichalcogenides with broken inversion symmetry can be controlled through spin and orbital DOFs owing to their valley-contrasting characters. Another important aspect of the spin and…

Materials Science · Physics 2017-08-31 T. Machida , Y. Kohsaka , R. Suzuki , M. Ochi , K. Iwaya , R. Arita , T. Hanaguri , Y. Iwasa