Zeeman splitting via spin-valley-layer coupling in bilayer MoTe2

Jiang, Chongyun; Liu, Fucai; Cuadra, Jorge; Huang, Zhilian; Li, Ké; Rasmita, Abdullah; Srivastava, Ajit; Liu, Zheng; Gao, Weibo

doi:10.1038/s41467-017-00927-4

Cited by 64 publications

(57 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The PL peaks in the magneto-PL spectra of the (σσ -) ( Fig. 4a) configuration exhibits a linear blue shift due to the valley Zeeman effects, 20,[44][45][46][47][48][49][50][51][52][53] and the size of the shift in a fixed B field is determined by the g-factor. It is evident from Fig.…”

Section: Resultsmentioning

confidence: 99%

Momentum-Dark Intervalley Exciton in Monolayer Tungsten Diselenide Brightened via Chiral Phonon

Wang

Choi

et al. 2019

ACS Nano

View full text Add to dashboard Cite

Inversion symmetry breaking and three-fold rotation symmetry grant the valley degree of freedom to the robust exciton in monolayer transition metal dichalcogenides (TMDCs), which can be exploited for valleytronics applications. However, the short lifetime of the exciton significantly constrains the possible applications. In contrast, dark exciton could be long-lived but does not necessarily possess the valley degree of freedom. In this work, we report the identification of the momentum-dark, intervalley exciton in monolayer WSe2 through low-temperature magnetophotoluminescence (PL) spectra. Interestingly, the intervalley exciton is brightened through the emission of a chiral phonon at the corners of the Brillouin zone (K point), and the pseudoangular momentum (PAM) of the phonon is transferred to the emitted photon to preserve the valley information. The chiral phonon energy is determined to be ~ 23 meV, based on the experimentally extracted exchange interaction (~ 7 meV), in excellent agreement with the theoretical expectation of 24.6 meV. The long-lived intervalley exciton with valley degree of freedom adds an exciting quasiparticle for valleytronics, and the coupling between the chiral phonon and intervalley exciton furnishes a venue for valley spin manipulation. KEYWORDS: intervalley exciton, chiral phonon, magneto-PL, time-resolved PL, tungsten diselenidethe lifetime of different excitonic complexes by a single exponential function = Ae −t/τ convolved with the response of the laser as a kernel.

show abstract

Section: Resultsmentioning

confidence: 99%

Momentum-Dark Intervalley Exciton in Monolayer Tungsten Diselenide Brightened via Chiral Phonon

Wang

Choi

et al. 2019

ACS Nano

View full text Add to dashboard Cite

show abstract

“…MoTe 2 is a very interesting layered material [43,44], which provides the fascinating opportunity to switch between semiconducting 2H and metallic phases by tuning strain or carrier concentration [45,46]. This allows working towards devices based on bias controlled phase changes in monolayer MoTe 2 [47,48].…”

Section: Excited State Spectroscopy In ML Mote2mentioning

confidence: 99%

Exciton States in Monolayer MoSe2 and MoTe2 Probed by Upconversion Spectroscopy

et al. 2018

View full text Add to dashboard Cite

Transitions metal dichalcogenides (TMDs) are direct semiconductors in the atomic monolayer (ML) limit with fascinating optical and spin-valley properties. The strong optical absorption of up to 20 % for a single ML is governed by excitons, electron-hole pairs bound by Coulomb attraction. Excited exciton states in MoSe2 and MoTe2 monolayers have so far been elusive due to their low oscillator strength and strong inhomogeneous broadening. Here we show that encapsulation in hexagonal boron nitride results in emission line width of the A:1s exciton below 1.5 meV and 3 meV in our MoSe2 and MoTe2 monolayer samples, respectively. This allows us to investigate the excited exciton states by photoluminescence upconversion spectroscopy for both monolayer materials. The excitation laser is tuned into resonance with the A:1s transition and we observe emission of excited exciton states up to 200 meV above the laser energy. We demonstrate bias control of the efficiency of this non-linear optical process. At the origin of upconversion our model calculations suggest an exciton-exciton (Auger) scattering mechanism specific to TMD MLs involving an excited conduction band thus generating high energy excitons with small wave-vectors. The optical transitions are further investigated by white light reflectivity, photoluminescence excitation and resonant Raman scattering confirming their origin as excited excitonic states in monolayer thin semiconductors.

show abstract

“…The generation and control of spin polarization is at the heart of this field. One recent progress along this direction is the light-induced spin and valley polarization in transition metal dichalcogenides (TMDCs) [14][15][16][17] and their heterostructures [18][19][20][21][22] . However, most of these studies were performed at low temperature with highquality samples, so as to reduce the intervalley scattering and increase the spin-valley polarization lifetime 23,24 .…”

mentioning

confidence: 99%

Room temperature near unity spin polarization in 2D Van der Waals heterostructures

Zhang

Liu

et al. 2020

Nat Commun

View full text Add to dashboard Cite

The generation and manipulation of spin polarization at room temperature are essential for 2D van der Waals (vdW) materials-based spin-photonic and spintronic applications. However, most of the high degree polarization is achieved at cryogenic temperatures, where the spin-valley polarization lifetime is increased. Here, we report on room temperature high-spin polarization in 2D layers by reducing its carrier lifetime via the construction of vdW heterostructures. A near unity degree of polarization is observed in PbI2 layers with the formation of type-I and type-II band aligned vdW heterostructures with monolayer WS2 and WSe2. We demonstrate that the spin polarization is related to the carrier lifetime and can be manipulated by the layer thickness, temperature, and excitation wavelength. We further elucidate the carrier dynamics and measure the polarization lifetime in these heterostructures. Our work provides a promising approach to achieve room temperature high-spin polarizations, which contribute to spin-photonics applications.

show abstract

Zeeman splitting via spin-valley-layer coupling in bilayer MoTe2

Cited by 64 publications

References 41 publications

Momentum-Dark Intervalley Exciton in Monolayer Tungsten Diselenide Brightened via Chiral Phonon

Momentum-Dark Intervalley Exciton in Monolayer Tungsten Diselenide Brightened via Chiral Phonon

Exciton States in Monolayer MoSe2 and MoTe2 Probed by Upconversion Spectroscopy

Room temperature near unity spin polarization in 2D Van der Waals heterostructures

Contact Info

Product

Resources

About