Gyanendra Dhakal

Tunability of the topological nodal-line semimetal phase in ZrSiX -type materials ( X=S, Se, Te )

The discovery of a topological nodal-line (TNL) semimetal phase in ZrSiS has invigorated the study of other members of this family. Here, we present a comparative electronic structure study of ZrSiX (where X = S, Se, Te) using angle-resolved photoemission spectroscopy (ARPES) and first-principles calculations. Our ARPES studies show that the overall electronic structure of ZrSiX materials comprises of the diamond-shaped Fermi pocket, the nearly elliptical-shaped Fermi pocket, and a small electron pocket encircling the zone center (

Dirac state in a centrosymmetric superconductor α-PdBi2

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Distinct multiple fermionic states in a single topological metal

) point, the M point, and the X point of the Brillouin zone, respectively. We also observe a small Fermi surface pocket along the M-

Discovery of topological nodal-line fermionic phase in a magnetic material GdSbTe

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Observation of Gapless Dirac Surface States in ZrGeTe

-M direction in ZrSiTe, which is absent in both ZrSiS and ZrSiSe. Furthermore, our theoretical studies show a transition from nodal-line to nodeless gapped phase by tuning the chalcogenide from S to Te in these material systems. Our findings provide direct evidence for the tunability of the TNL phase in ZrSiX material systems by adjusting the spin-orbit coupling (SOC) strength via the X anion.

Observation of Dirac state in half-Heusler material YPtBi

Topological superconductor (TSC) hosting Majorana fermions has been established as a milestone that may shift our scientific trajectory from research to applications in topological quantum computing. Recently, superconducting Pd-Bi binaries have attracted great attention as a possible medium for the TSC phase as a result of their large spin-orbit coupling strength. Here, we report a systematic high-resolution angle-resolved photoemission spectroscopy (ARPES) study on the normal state electronic structure of superconducting

Observation of a Dirac state in a half-Heusler material YPtBi

\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{PdBi}}_{2}\phantom{\rule{4pt}{0ex}}({T}_{c}=1.7

Dirac-like dispersion in nearly compensated Dirac semimetal ZrAs 2

K). Our results show the presence of Dirac states at higher-binding energy with the location of the Dirac point at 1.26 eV below the chemical potential at the zone center. Furthermore, the ARPES data indicate multiple band crossings at the chemical potential, consistent with the metallic behavior of

Dirac State in a Centrosymmetric Superconductor α-PdBi 2

\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{PdBi}}_{2}

Observation of topological nodal-line fermionic phase in GdSbTe

. Our detailed experimental studies are complemented by first-principles calculations, which reveal the presence of surface Rashba states residing in the vicinity of the chemical potential. The obtained results provide an opportunity to investigate the relationship between superconductivity, topology, and the Majorana fermion, as well as explore pathways to possible future platforms for topological quantum computing.