Wannier function approach to realistic Coulomb interactions in layered materials and heterostructures

Rösner, Malte; Şaşıoğlu, E.; Friedrich, Christoph; Blügel, Stefan; Wehling, T. O.

doi:10.1103/physrevb.92.085102

Cited by 73 publications

(107 citation statements)

References 44 publications

(43 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This conclusion should be generally applicable also to other superconducting 2d materials such as NbSe 2 9 and particularly the electron doped TMDCs like WS 2 or MoSe 2 10,11 because of their similar electronic and phononic structure. (WFCE) 33 to include the screening effects of substrates, as described in the following. The bare interaction matrix U αβ (q) in the orbital basis α, β ∈ {d z 2 , d xy , d x 2 y 2 } of the Mo atoms is obtained for the freestanding undoped material via RPA calculations using the Spex and Fleur software codes 31,32 .…”

Section: Discussionmentioning

confidence: 99%

“…µ * = 0.13 24,33,38 , is not sufficient in the case of electron doped MoS 2 to describe the influence of the Coulomb interaction directly at the transition to the superconducting phase. However, the drop in the critical temperature of TMDCs 6,7,9,16,18 when going from the bulk or multilayer-system to a monolayer cannot be caused by enhanced Coulomb interactions, because the values of the electron-phonon coupling are much larger than the µ * ≈ 0.13, which we find in the region of optimal doping independently of the dielectric environment of the MoS 2 monolayer.…”

Section: Electron-phonon Coupling Driven Superconductivitymentioning

confidence: 99%

“…In the long-wavelength limit, ε 1 (q) is fully determined by the dielectric background: ε 1 (q → 0) = ε sub . In the opposite limit (q 1Å −1 ), screening in the undoped case is solely due to the microscopic inter-band polarizability of the MoS 2 layer itself, ε 1 (q) ≈ 9.3 ≡ ε ∞ , but unaffected by the dielectric environment 33,34 .…”

Section: Electronic Structure and Coulomb Interactionsmentioning

confidence: 99%

“…1(b). This allows us to compute the screened matrix elements V αβ (q) using the recently developed Wannier function continuum electrostatics approach (WFCE) 33 . To this end, we need to assign a physical thickness d ≈ 9.1Å to the monolayer of MoS 2 .…”

Section: Electronic Structure and Coulomb Interactionsmentioning

confidence: 99%

See 3 more Smart Citations

Interplay of screening and superconductivity in low-dimensional materials

et al. 2016

Self Cite

View full text Add to dashboard Cite

A quantitative description of Coulomb interactions is developed for two-dimensional superconducting materials, enabling us to compare intrinsic with external screening effects, such as those due to substrates. Using the example of a doped monolayer of MoS 2 embedded in a tunable dielectric environment, we demonstrate that the influence of external screening is limited to a length scale, bounded from below by the effective thickness of the quasi two-dimensional material and from above by its intrinsic screening length. As a consequence, it is found that unconventional Coulomb driven superconductivity cannot be induced in MoS 2 by tuning the substrate properties alone. Our calculations of the retarded Morel-Anderson Coulomb potential µ * reveal that the Coulomb interactions, renormalized by the reduced layer thickness and the substrate properties, can shift the onset of the electron-phonon driven superconducting phase in monolayer MoS 2 but do not significantly affect the critical temperature at optimal doping.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Electron-phonon Coupling Driven Superconductivitymentioning

confidence: 99%

Section: Electronic Structure and Coulomb Interactionsmentioning

confidence: 99%

Section: Electronic Structure and Coulomb Interactionsmentioning

confidence: 99%

See 2 more Smart Citations

Interplay of screening and superconductivity in low-dimensional materials

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…We have obtained the quasiparticle band structure and Coulomb matrix elements of monolayer WS 2 by first-principle GoWo calculations. Screening from the substrate is additionally incorporated in the Coulomb matrix elements [132]. The exciton shift due to the excited carriers is calculated with microscopic semiconductor Bloch equations in a screened-exchange Coulomb-hole approximation (SXCH) -see Section 7.7.1.…”

Section: At Low Density: Plasma Contributionmentioning

confidence: 99%

Coherent Light-Matter Interactions in Monolayer Transition-Metal Dichalcogenides

Sie

2018

Springer Theses

View full text Add to dashboard Cite

Semiconductors that are thinned down to a few atomic layers can exhibit novel properties beyond those encountered in bulk forms. Transition-metal dichalcogenides (TMDs) such as MoS 2 , WS 2 and WSe 2 are prime examples of such semiconductors. They appear in layered structure that can be reduced to a stable single layer where remarkable electronic properties can emerge. Monolayer TMDs have a pair of electronic valleys which have been proposed as a new way to carry information in next generation devices, called valleytronics. However, these valleys are normally locked in the same energy level, which limits their potential use for applications.This dissertation presents the optical methods to split their energy levels by means of coherent light-matter interactions. Experiments were performed in a pump-probe technique using a transient absorption spectroscopy on MoS 2 and WS 2 , and a newly developed XUV light source for time and angle-resolved photoemission spectroscopy (TR-ARPES) on WSe 2 and WTe 2 . Hybridizing the electronic valleys with light allows us to optically tune their energy levels in a controllable valley-selective manner. In particular, by using off-resonance circularly polarized light at small detuning, we can tune the energy level of one valley through the optical Stark effect. At larger detuning, we observe a separate contribution from the so-called Bloch-Siegert effect, a delicate phenomenon that has eluded direct observation in solids. The two effects obey opposite selection rules, which enables us to separate the two effects at two different valleys.Monolayer TMDs also possess strong Coulomb interaction that enhances many-body interactions between excitons, both bonding and non-bonding interactions. In the former, bound excitonic quasiparticles such as biexcitons play a unique role in coherent light-matter interactions where they couple the two valleys to induce opposite energy shifts. In the latter, non-bonding interactions between excitons are found to exhibit energy shifts that effectively mimics the Lennard-Jones interactions between atoms. Through these works, we demonstrate new methods to optically tune the energy levels of electronic valleys in monolayer TMDs. AcknowledgmentsFirst and foremost, I would like to thank my advisor Prof. Nuh Gedik for his mentorship and support. He has been a constant source of inspiration since I first started my graduate studies. Actually it was even before that. I remember my first meeting at a conference in Boston where he presented a real-time image of crystalline lattice motion. The idea of watching Michael Jackson performing Billie Jean flashed through my head, because he was that cool and inspiring, and he continues to be so. He has been a tremendous support since day one, where I was given the opportunity to design and build the XUV beamline for ARPES in the lab as well as the freedom to build the white-light setup next to it. His vigor to make new innovations in timeresolved experiments is always inspiring. Throughout my graduate studies, he...

show abstract

Selfenergy Effect on the Magnetic Ordering Transition in the Mono‐ and Bilayer Honeycomb Hubbard Model

Honerkamp

2017

Annalen der Physik

View full text Add to dashboard Cite

We investigate the impact of electron self-energy corrections on potential antiferromagnetic ordering instabilities in mono-and bilayer graphene, modeled by a Hubbard-type lattice model with onsite interactions among the electrons, using a self-consistent random phase approximation (RPA). In qualitative agreement with earlier studies we find that the electronic interactions cause non-Fermi liquid behavior at low energies. In self-consistent RPA, the transition scales for antiferromagnetic ordering are renormalized significantly by these self-energy effects, both for interaction-driven and temperature-driven cases.

show abstract

Wannier function approach to realistic Coulomb interactions in layered materials and heterostructures

Cited by 73 publications

References 44 publications

Interplay of screening and superconductivity in low-dimensional materials

Interplay of screening and superconductivity in low-dimensional materials

Coherent Light-Matter Interactions in Monolayer Transition-Metal Dichalcogenides

Selfenergy Effect on the Magnetic Ordering Transition in the Mono‐ and Bilayer Honeycomb Hubbard Model

Contact Info

Product

Resources

About