187 citations · 800 across the 20 of their papers we have counts for
20 papers
Intervalley electron-hole exchange interaction and impurity-assisted recombination of indirect excitons in WS and WSe monolayers
Pengke Li, Cedric Robert, Dinh Van Tuan +3
The variety of excitonic states in tungsten-based dichalcogenide monolayers stems from unique interplay between the spin and valley degrees of freedom. One of the exciton species i…
Mid-infrared photoconductivity spectra of single tellurium nanowires]{Mid-infrared photoconductivity spectra of single tellurium nanowires
Pengke Li
Due to its low bandgap and high optical efficiency, tellurium is considered an important material candidate for mid-infrared applications. Taking advantage of its structural anisot…
Origins of electromagnetic anisotropy in monolayer black phosphorus
Pengke Li
Contrary to empirical observations, lowest-order theory predicts that monolayer black phosphorus ("phosphorene") is completely immune to zigzag-polarized optical ex…
Excitons without effective mass: biased bilayer graphene
Pengke Li, Ian Appelbaum
Understanding the dynamics of excitons in two dimensional semiconductors requires a theory that incorporates the essential physics distinct from their three-dimensional counterpart…
Kramers' revenge
Pengke Li, Ian Appelbaum
The combination of space inversion and time reversal symmetries result in doubly-degenerate Bloch states with opposite spin. Many lattices with these symmetries can be constructed…
Robust zero-energy bound states in a helical lattice
Pengke Li, Jay D. Sau, Ian Appelbaum
Atomic-scale helices exist as motifs for several material lattices. We examine a tight-binding model for a single one-dimensional monatomic chain with a p-orbital basis coiled into…
Intrinsic two-dimensional state on the pristine surface of tellurium
Pengke Li, Ian Appelbaum
Using a tight-binding description, we show how the zero-dimensional state bound to the edge of a single one-dimensional helical chain of tellurium atoms evolves into two-dimensiona…
Electrons, holes, and spin in the IV-VI monolayer 'four-six-enes'
Ian Appelbaum, Pengke Li
Bandedge states in the indirect-gap group-IV metal monochalcogenide monolayers ('four-six-enes' such as SnS, GeTe, etc.) inherit the properties of nearby reciprocal space points of…
Interpreting current-induced spin polarization in topological insulator surface states
Pengke Li, Ian Appelbaum
Several recent experiments on three-dimensional topological insulators claim to observe a large charge current-induced non-equilibrium ensemble spin polarization of electrons in th…
Spin polarization control in a 2-dimensional semiconductor
Ian Appelbaum, Pengke Li
Long carrier spin lifetimes are a double-edged sword for the prospect of constructing "spintronic" logic devices: Preservation of the logic variable within the transport channel or…
Symmetry, distorted bandstructure, and spin-orbit coupling of (group-III) metal-monochalcogenide monolayers
Pengke Li, Ian Appelbaum
The electronic structure of (group-III) metal-monochalcogenide monolayers exhibits many unusual features. Some, such as the unusually distorted upper valence band dispersion we des…
Electrons and holes in phosphorene
Pengke Li, Ian Appelbaum
We present a symmetry analysis of electronic bandstructure including spin-orbit interaction close to the insulating gap edge in monolayer black phosphorus ('phosphorene'). Expressi…
Self-consistent model of spin accumulation magnetoresistance in ferromagnet-insulator-semiconductor tunnel junctions
Ian Appelbaum, Holly N. Tinkey, Pengke Li
Spin accumulation in a paramagnetic semiconductor due to voltage-biased current tunneling from a polarized ferromagnet is experimentally manifest as a small additional spin-depende…
Inelastic electron tunneling spectroscopy of local "spin accumulation" devices
Holly N. Tinkey, Pengke Li, Ian Appelbaum
We investigate the origin of purported "spin accumulation" signals observed in local "three-terminal" (3T) measurements of ferromagnet/insulator/n-Si tunnel junctions using inelast…
Anisotropy-driven spin relaxation in germanium
Pengke Li, Jing Li, Lan Qing +2
A unique spin depolarization mechanism, induced by the presence of g-factor anisotropy and intervalley scattering, is revealed by spin transport measurements on long-distance germa…
Spin-dependent optical properties in strained silicon and germanium
Pengke Li, Dhara Trivedi, Hanan Dery
We present a comprehensive theory of the circularly polarized luminescence and its dependence on strain in spin-polarized Si and Ge. Symmetries of wavefunctions and interactions ar…
Intrinsic Spin Lifetime of Conduction Electrons in Germanium
Pengke Li, Yang Song, Hanan Dery
We investigate the intrinsic spin relaxation of conduction electrons in germanium due to electron-phonon scattering. We derive intravalley and intervalley spin-flip matrix elements…
Silicon spin communication
Hanan Dery, Yang Song, Pengke Li +1
Recent experimental breakthroughs have demonstrated that the electron spin in silicon can be reliably injected and detected as well as transferred over distances exceeding 1 mm. We…
Spin-Orbit Symmetries of Conduction Electrons in Silicon
Pengke Li, Hanan Dery
We derive a spin-dependent Hamiltonian that captures the symmetry of the zone edge states in silicon. We present analytical expressions of the spin-dependent states and of spin rel…
Theory of Spin-Dependent Phonon-Assisted Optical Transitions in Silicon
Pengke Li, Hanan Dery
A theory for the relation between the spin polarization and luminescence in silicon is presented. The theory provides intuitive relations for phonon-assisted optical transitions be…