In this paper, we calculate the low-lying spectra of a single-electron magnetic quantum ring with an offcenter Coulomb impurity, where the magnetic field is zero within the ring and constant elsewhere. The impurity, e...In this paper, we calculate the low-lying spectra of a single-electron magnetic quantum ring with an offcenter Coulomb impurity, where the magnetic field is zero within the ring and constant elsewhere. The impurity, either an acceptor or a donor, is located at a distance d as measured from the plane of the ring along the vertical z direction. The magnetic moments are found in order to get visible discontinuities at the points of the ground-state orbital angular momentum L transitions induced by magnetic fields.展开更多
The widespread applications of thermoelectric(TE)materials in power generation and solid-state cooling require improving their TE figure of merit(ZT)significantly.Recently,GeTe-based alloys have shown great promise as...The widespread applications of thermoelectric(TE)materials in power generation and solid-state cooling require improving their TE figure of merit(ZT)significantly.Recently,GeTe-based alloys have shown great promise as mid-temperature TE materials with superhigh TE performance,mostly due to their relatively high-degeneracy band structures and low lattice thermal conductivity.In this perspective,we review the most recent progress of the GeTe-based TE alloys from the view of phase and defect engineering.These two strategies are the most widely-used and efficient approaches in GeTe-based alloys to optimize the transport properties of electrons and phonons for high ZT.The phase transition from rhombohedral to cubic structure is believed to improve the band convergence of GeTe-based alloys for higher electrical performance.Typical defects in GeTe-based alloys include the point defects from Ge vacancies and substitutional dopants,linear and planar defects from Ge vacancies.The defect engineering of GeTe-based alloys is important not only for optimizing the carrier density but also for tuning the band structure and phonon-scattering processes.The summarized strategies in this review can also be used as a reference for guiding the further development of GeTe-based alloys and also other TE materials.展开更多
基金The project supported by National Natural Science Foundation of China under Grant Nos. 50371058 and 90103028
文摘In this paper, we calculate the low-lying spectra of a single-electron magnetic quantum ring with an offcenter Coulomb impurity, where the magnetic field is zero within the ring and constant elsewhere. The impurity, either an acceptor or a donor, is located at a distance d as measured from the plane of the ring along the vertical z direction. The magnetic moments are found in order to get visible discontinuities at the points of the ground-state orbital angular momentum L transitions induced by magnetic fields.
基金supported by the National Natural Science Foundation of China(21805196)Natural Science Foundation of Guangdong Province,China(2018A030310416,2019A1515010832)。
文摘The widespread applications of thermoelectric(TE)materials in power generation and solid-state cooling require improving their TE figure of merit(ZT)significantly.Recently,GeTe-based alloys have shown great promise as mid-temperature TE materials with superhigh TE performance,mostly due to their relatively high-degeneracy band structures and low lattice thermal conductivity.In this perspective,we review the most recent progress of the GeTe-based TE alloys from the view of phase and defect engineering.These two strategies are the most widely-used and efficient approaches in GeTe-based alloys to optimize the transport properties of electrons and phonons for high ZT.The phase transition from rhombohedral to cubic structure is believed to improve the band convergence of GeTe-based alloys for higher electrical performance.Typical defects in GeTe-based alloys include the point defects from Ge vacancies and substitutional dopants,linear and planar defects from Ge vacancies.The defect engineering of GeTe-based alloys is important not only for optimizing the carrier density but also for tuning the band structure and phonon-scattering processes.The summarized strategies in this review can also be used as a reference for guiding the further development of GeTe-based alloys and also other TE materials.
