| 1. |
- Jakhar, Alka, et al.
(författare)
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Integration of Nanometer-Thick 1T-TaS2 Films with Silicon for an Optically Driven Wide-Band Terahertz Modulator
- 2020
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Ingår i: ACS Applied Nano Materials. - : AMER CHEMICAL SOC. - 2574-0970. ; 3:11, s. 10767-10777
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Tidskriftsartikel (refereegranskat)abstract
- The amplitude of terahertz (THz) waves is modulated optically by a pumping laser source, and the effect of optical power on modulation depth is systematically investigated in this work. The reported THz modulator is based on a conducting transition metal dichalcogenide (TMD), that is, a nanometer-thick thin film of tantalum disulfide (TaS2) grown on a high-resistivity silicon (Si) substrate. The Raman spectrum confirms the formation of the 1T phase of TaS2. Modulation depths of 69.3 and 46.8% have been achieved at 0.1 THz and 0.9 THz frequency, respectively, under a low pumping power of 1 W/cm(2). A constant higher modulation depth in the wide frequency range reveals the broadband response of the THz modulator. Under the same conditions, the modulation increased twice as compared to bare Si after annealing at 300 degrees C in the presence of air. Furthermore, numerical analysis based on the finite-difference time domain shows that a greater number of photogenerated charge carriers are present near the interface of Si and TaS2, which leads to enhancement in modulation. The utilization of 1T-TaS2 imparts potential to these TMDs in the wide THz frequency range and unfolds the possibilities for their use in THz imaging, wireless communication, and detection processes.
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| 2. |
- Mudgal, Richa, et al.
(författare)
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Magnetic-Proximity-Induced Efficient Charge-to-Spin Conversion in Large-Area PtSe2/Ni80Fe20 Heterostructures
- 2023
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Ingår i: NANO LETTERS. - 1530-6984 .- 1530-6992. ; 23:24, s. 11925-11931
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Tidskriftsartikel (refereegranskat)abstract
- As a topological Dirac semimetal with controllable spin-orbit coupling and conductivity, PtSe2, a transition-metal dichalcogenide, is a promising material for several applications, from optoelectrics to sensors. However, its potential for spintronics applications has yet to be explored. In this work, we demonstrate that the PtSe2/Ni80Fe20 heterostructure can generate large damping-like current-induced spin-orbit torques (SOT), despite the absence of spin-splitting in bulk PtSe2. The efficiency of charge-to-spin conversion is found to be -0.1 +/- 0.02 nm(-1) in PtSe2/Ni80Fe20, which is 3 times that of the control sample, Ni80Fe20/Pt. Our band structure calculations show that the SOT due to PtSe2 arises from an unexpectedly large spin splitting in the interfacial region of PtSe2 introduced by the proximity magnetic field of the Ni80Fe20 layer. Our results open up the possibilities of using large-area PtSe2 for energy-efficient nanoscale devices by utilizing proximity-induced SOT.
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