A Study of the Phase Change Material Mo1-xWxTe2

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APS March Meeting 2018

Volume 63, Number 1

Monday–Friday, March 5–9, 2018; Los Angeles, California

Session L36: 2D Materials - Topological States

11:15 AM–2:15 PM, Wednesday, March 7, 2018
LACC Room: 410

Sponsoring Unit: DMP
Chair: Pablo Jarrillo-Herrero, MIT

Abstract ID: BAPS.2018.MAR.L36.9

Abstract: L36.00009 : A Study of the Phase Change Material Mo_1-xW_xTe₂

1:39 PM–1:51 PM

Abstract

Presenter:

Sean Oliver
(Physics and Astronomy, George Mason University)

Authors:

Sean Oliver
(Physics and Astronomy, George Mason University)

Ryan Beams
(Material Measurement Laboratory, National Institute of Standards and Technology)

Sergiy Krylyuk
(Material Measurement Laboratory, National Institute of Standards and Technology)

Irina Kalish
(Material Measurement Laboratory, National Institute of Standards and Technology)

Arunima Singh
(Material Measurement Laboratory, National Institute of Standards and Technology)

Alina Bruma
(Material Measurement Laboratory, National Institute of Standards and Technology)

Francesca Tavazza
(Material Measurement Laboratory, National Institute of Standards and Technology)

Jaydeep Joshi
(Physics and Astronomy, George Mason University)

Iris Stone
(Physics and Astronomy, George Mason University)

Stephan Stranick
(Material Measurement Laboratory, National Institute of Standards and Technology)

Albert Davydov
(Material Measurement Laboratory, National Institute of Standards and Technology)

Patrick Vora
(Physics and Astronomy, George Mason University)

Structural polymorphism in the transition metal dichalcogenide (TMD) MoTe₂ is ideal for enabling ultrathin phase change memories. Under ambient conditions, MoTe₂ crystallizes in the 2H semiconducting phase, but can be grown in the 1T’ semimetallic phase that transitions into the T_d phase below ~250 K. Alloying MoTe₂ with WTe₂ is theorized to reduce the barrier between the 2H and 1T’ phases, which may improve the efficiency of TMD-based memories and provide on-demand topological phase transitions. Contradictory reports of the Mo_1-xW_xTe₂ phase diagram [1,2] demonstrate the need for new investigations of this alloy system. Here, we combine Raman spectroscopy, x-ray diffraction, scanning transmission electron microscopy, and density-functional theory to explore the phase boundaries of bulk Mo_1-xW_xTe₂ alloys. Our work confirms the existence of 2H, 1T’, and T_dregions, as well as a two-phase 1T’-T_d region in the MoTe₂-WTe₂ system [3]. We extract the phonon correlation length through the phonon confinement model, identify disorder-enhanced two-phonon scattering, and observe disorder-activation of infrared modes. These results provide a foundation for future applications of the Mo_1-xW_xTe₂alloys.

[1] Rhodes et al. Nano Lett. 2017 [2] Lv et al. Sci. Rep. 2017 [3] Oliver et al. 2D Mat. 2017

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2018.MAR.L36.9

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Bulletin of the American Physical Society

APS March Meeting 2018

Volume 63, Number 1

Monday–Friday, March 5–9, 2018; Los Angeles, California

Session L36: 2D Materials - Topological States

Abstract: L36.00009 : A Study of the Phase Change Material Mo1-xWxTe2

Presenter:

Authors:

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Abstract: L36.00009 : A Study of the Phase Change Material Mo_1-xW_xTe₂