Published Research

1. Electric polarization near vortices in the extended Kitaev model

Starting from a three-orbital Hubbard–Kanamori model, we used perturbative low-energy projection to derive a spin-dependent charge-density operator in the \(j_{\mathrm{eff}}=1/2\) sector. A real-space, self-consistent Majorana mean-field calculation for the extended \(JK\Gamma\) model, benchmarked against exact results in the Kitaev limit, yielded the charge redistribution and electric quadrupole tensor \(Q_{\alpha\beta}\) near \(\mathbb{Z}_2\) vortices. We determined how exchange anisotropies affect quadrupolar vortex interactions and how a local electrostatic potential reduces the mean-field vortex gap. Electrically assisted vortex nucleation was suggested by extrapolating solutions beyond the regime of numerical convergence, not demonstrated as a controlled dynamical process.

2. Scanning tunneling spectroscopy of Majorana zero modes in a Kitaev spin liquid

We combined exact dynamical spin correlations in the Kitaev model with spin-dependent cotunneling amplitudes derived from a projected tip–spin-liquid–substrate Hamiltonian. The resulting differential tunneling conductance exhibits a spatially dependent staircase near vortex-bound Majorana zero modes. Its voltage thresholds encode both the zero-mode contribution and changes in the flux sector, providing spatial and spectroscopic signatures for comparison with conventional bound states.

3. Local spin-flip transitions induced by magnetic quantum impurities in two-dimensional magnets

We studied magnetic adatoms and substitutional impurities in partially polarized two-dimensional van der Waals magnets without spin-rotation \(U(1)\) symmetry. Continuum analysis, spin-wave \(T\)-matrix calculations, and small-system exact diagonalization revealed field-driven local spin-flip transitions when an impurity-bound magnon softens through zero energy. Their distinct field- and voltage-dependent tunneling signatures provide a conventional bound-state mechanism against which proposed signatures of fractionalization must be compared.

4. Gapless excitations in non-Abelian Kitaev spin liquids with line defects

We studied counterpropagating chiral Majorana modes along line defects in non-Abelian Kitaev spin liquids. Earlier microscopic interface analyses established that local spin perturbations do not generate the relevant interedge mass term in the weak-defect regime, despite its allowance by continuum power counting. Building on this mechanism, we determined the field-dependent critical defect coupling within self-consistent Majorana mean-field theory. Projection of the spin operator onto the gapless defect modes predicts a local nuclear relaxation rate \(1/T_1 \propto T^3\), corresponding to scaling dimension \(\Delta=2\).

Theses and Dissertations

• PhD in Physics (Condensed Matter Theory) (Universidade Federal do Rio Grande do Norte (UFRN), Natal, Brazil, 2020–2024): Majorana mean-field theory with \(\mathbb{Z}_2\) vortices: Electrical tests in the extended Kitaev model · Supervisor: Prof. Rodrigo G. Pereira · UFRN Repository Record.
• MSc in Physics (Condensed Matter Theory) (Universidade Federal do Rio Grande do Norte (UFRN), Natal, Brazil, 2019–2021): Gapless excitations in Kitaev materials with defects · Supervisor: Prof. Rodrigo G. Pereira · UFRN Repository Record.
• BSc in Physics, cum laude (Universidade Federal do Rio Grande do Norte (UFRN), Natal, Brazil, 2015–2018): Duality in Dirac theories via Bosonization · Supervisor: Prof. Rodrigo G. Pereira · UFRN Repository Record.