Riassunto analitico
Within this thesis, the intermetallic compound LaIn3 and the Sn doped series LaIn(3-x)Sn(x) (x=0.12, 0.15) are investigated by means of capacitive torque magnetometry in order to probe quantum oscillations (QOs) in the magnetization, known as the de Haas-van Alphen (dHvA) effect. The primary aim of this Master’s project is to determine the Fermi surface and investigate the charge-transport properties of LaIn3 within the Onsager-Lifshitz framework (effective cyclotron masses of the carriers, Dingle temperature, Berry phase etc.). Then, the shape of the Fermi surface and the electronic properties of the binary and pseudobinary compound are studied as a function of the Sn concentration. The experimental purpose is motivated by preliminary tight-binding band structure calculations which highlight the presence of Dirac crossings due to the presence of p-orbitals aroused by the LaIn3 structure itself over its Fermi level. This Master's thesis is included in a wider project, which final aim is to demonstrate the possibility of the Fermi level tuning in LaIn3 by systematic substitution of Sn. The successful demonstration of the tunability by doping would lead to the observation of the signature of Dirac fermions and the concrete realization of the topological engineering for LaIn3. The first results highlight a complex Fermi surface for LaIn3, characterized by many electron- and hole-pockets, either at low and high frequencies with light effective cyclotron masses, with the evidence of possible magnetic breakdown and/or magnetic interaction. Moreover, the Berry phase analysis suggests the non-trivial band topology of LaIn3. Whereas, the characterization of the Sn-doped compounds indicate that the Fermi surface is reduced in size, with the total suppression of the high frequency pockets. The remarkable results obtained in this Master's project suggest the necessity of performing higher field (>16 T) characterizations, in order to pursue the doping study and to probe the Fermi surface of LaIn3 in more details, investigating the magnetic breakdown/interaction and the frequency shift observed for some orbits at the lowest temperatures.
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Abstract
Within this thesis, the intermetallic compound LaIn3 and the Sn doped series LaIn(3-x)Sn(x) (x=0.12, 0.15) are investigated by means of capacitive torque magnetometry in order to probe quantum oscillations (QOs) in the magnetization, known as the de Haas-van Alphen (dHvA) effect. The primary aim of this Master’s project is to determine the Fermi surface and investigate the charge-transport properties of LaIn3 within the Onsager-Lifshitz framework (effective cyclotron masses of the carriers, Dingle temperature, Berry phase etc.). Then, the shape of the Fermi surface and the electronic properties of the binary and pseudobinary compound are studied as a function of the Sn concentration. The experimental purpose is motivated by preliminary tight-binding band structure calculations which highlight the presence of Dirac crossings due to the presence of p-orbitals aroused by the LaIn3 structure itself over its Fermi level. This Master's thesis is included in a wider project, which final aim is to demonstrate the possibility of the Fermi level tuning in LaIn3 by systematic substitution of Sn. The successful demonstration of the tunability by doping would lead to the observation of the signature of Dirac fermions and the concrete realization of the topological engineering for LaIn3. The first results highlight a complex Fermi surface for LaIn3, characterized by many electron- and hole-pockets, either at low and high frequencies with light effective cyclotron masses, with the evidence of possible magnetic breakdown and/or magnetic interaction. Moreover, the Berry phase analysis suggests the non-trivial band topology of LaIn3. Whereas, the characterization of the Sn-doped compounds indicate that the Fermi surface is reduced in size, with the total suppression of the high frequency pockets. The remarkable results obtained in this Master's project suggest the necessity of performing higher field (>16 T) characterizations, in order to pursue the doping study and to probe the Fermi surface of LaIn3 in more details, investigating the magnetic breakdown/interaction and the frequency shift observed for some orbits at the lowest temperatures.
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