Update research.html

research.html

@@ -179,15 +179,25 @@ <h1 class="sitetitle">Dai Q. Ho</h1>
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+            Rare-earth monopnictides (RE-Vs) are semimetals with low charge carrier concentration due to a small overlap between electron and hole pockets.
+            Thin films of RE-V semimetals are expected to turn into semiconductors due to quantum confinement effects (QCE), lifting the overlap between electron pockets at Brillouin zone edges (X) and hole pockets at the zone center (Γ).    
             In this project, we have shown that, contrary to conventional expectation, bulk semimetallic rare-earth monopnictides (RE-V) could be transitioned to a quantum spin Hall insulator phase in ultra-thin films.<br>
+            This is attributed to a strong QCE on the in-plane electron pockets and the lack of quantum confinement on the out-of-plane pocket projected onto the zone center, resulting in a band inversion.
+            Spin–orbit coupling (SOC) opens a sizable nontrivial gap in the band structure of ultrathin films.
+            Such effect is anticipated to be general in rare-earth monopnictides and may lead to interesting phenomena when coupled with the 4f magnetic moments present in other members of this family of materials.    
 
             <strong> Project 4/ Tuning band topology of rare-earth monopnictides by epitaxial strain </strong><br>
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+            Rare-earth monopnictide (RE-V) semimetal crystals subjected to hydrostatic pressure have shown interesting trends in magnetoresistance, magnetic ordering, and superconductivity, with theory predicting pressure-induced band inversion. 
+            Yet, thus far, there have been no direct experimental reports of interchanged band order in RE-Vs due to strain.
             In this project, we have shown that the band topology of GdSb, an AFM semimetallic RE-V in bulk, could be tuned going from trivial semimetal to nontrival one by using epitaxial strain.
+            This work studies the evolution of band topology in biaxially strained GdSb(001) epitaxial films using angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT). 
+            As biaxial strain is tuned from tensile to compressive strain, the gap between the hole and the electron bands dispersed along [001] decreases. 
+            The conduction and valence band shifts seen in DFT and ARPES measurements are explained by a tight-binding model that accounts for the orbital symmetry of each band.
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