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BEGIN:VEVENT
DTSTAMP:20260813T004621Z
LAST-MODIFIED:20201214T210957Z
DTSTART:20201218T150000Z
DTEND:20201218T160000Z
UID:event2389@bu.edu
URL:http://physics.bu.edu/internal/events/show/2389
SUMMARY:Probing nodal point singularities using resonant inelastic X-ray sc
	attering
DESCRIPTION:Featuring Anirudh Chandrasekaran\, Boston University\, Physics 
	Department\n\nPart of the Departmental Seminars.\n\nIn this talk I will dis
	cuss a recent work of ours\, in which we worked out the theory of resonant 
	inelastic x-ray scattering (RIXS) of electronic excitations in topological 
	nodal-point semimetals. RIXS is a one photon in - one photon process which 
	imparts both energy and momentum to the material\, effectively causing part
	icle hole excitations across the Fermi level. We derived the general cross-
	section for RIXS in band structures in the fast collision approximation\, e
	lucidating the effects of symmetry and atomic form factors. Spectral patter
	ns in the geometry and intensity of the RIXS response reveal the presence o
	f nodal points in the band structure. To demonstrate this\, we first calcul
	ated analytically the geometry and functional form of the particle-hole con
	tinuum of Weyl nodes\, encapsulated in the energy-resolved joint density of
	 states. We then performed an exact calculation of the RIXS intensity for a
	 nodal point observed in transition-metal monosilicides\, using the band st
	ructure determined by density functional theory. We found that the RIXS spe
	ctrum contains the characteristics of the particle-hole continuum of nodal 
	points and can thus be used to identify them. We concluded that RIXS can de
	tect signatures of topological origin in the three-dimensional band structu
	res of materials and is especially pertinent in settings that are inaccessi
	ble to ARPES\, such as for unoccupied bands and in magnetic fields. This pa
	ves the way for RIXS as a robust technique for studying band excitations in
	 future experiments.\n\n\n----\n\nZOOM: https://bostonu.zoom.us/j/946338295
	36?pwd=bFhOdlRXVWY4OC9RSmxvdHA3VGNRZz09
LOCATION: \, \, 
STATUS:CONFIRMED
CLASS:PUBLIC
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