Co-worker accused me of theft at office, should I file a defamation case?

I work at a tech startup in Bengaluru, and recently a co-worker publicly accused me of stealing company hardware. This accusation is false but has damaged my reputation among peers and management. I have tried to clarify with HR, but they seem to side with him without evidence. Should I consider filing a defamation lawsuit? What are my options to clear my name and protect my job?