Nano MASc Seminar: Probing Ising Superconductivity and Light-induced Phase Transitions in Two-dimensional Transition Metal DichalcogenidesExport this event to calendar

Wednesday, April 10, 2019 — 3:00 PM EDT

Candidate: Tina Elayne Dekker

Title: Probing Ising Superconductivity and Light-induced Phase Transitions in Two-dimensional Transition Metal Dichalcogenides

 

Date: April 8, 2019

Time: 2:00PM

Place: QNC 4104

Supervisor(s): Tsen, Adam Wei (Chemistry) - Kim, Na Young

 

Abstract:

2H-NbSe2 is a superconducting transition metal dichalcogenide that retains its superconductivity in its two-dimensional (2D) form. Owing to strong spin orbit coupling, 2D 2H-NbSe2 demonstrates unconventional superconductivity that allows both spin-singlet and spin-triplet Cooper pairing. There is experimental and theoretical evidence that 2D 2H-NbSe2 is an Ising superconductor. However, a direct measurement of its Ising nature has not yet been proven. In this thesis, I present the results of measurements on a 2H-NbSe2 superconducting spin filter tunnel junction fabricated with mechanically exfoliated 2D flakes.

Using this device geometry, it may be possible to elucidate the pairing nature in 2H-NbSe2.

   Intense ultrashort laser pulses can photo-excite non-equilibrium states in materials leading to transient new phases and exotic states. In bulk materials these photo-exited states are short-lived. 1T’-MoTe2 in bulk form undergoes a reversible transition at ~250 K from the monoclinic phase (1T’-MoTe2) to the inversion-symmetry breaking, orthorhombic phase (Td-MoTe2).

Td-MoTe2 is a candidate type II Weyl semimetal that is predicted to demonstrate exotic quantum phenomena. These phases in 2D

MoTe2 flakes are characterized using ultrafast optical-pump probe techniques. The results indicate a permanent photo-induced structural change occurs in thin Td-MoTe2 at high fluences. Given the durability of this structural change, further characterization of the sample is achieved using magnetotransport measurements.

Location 
QNC
Room 1201
200 University Avenue West

Kitchener, ON N2L 3G1
Canada

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