While the broader concept of design thinking has a long history, the contemporary definition of Design Thinking has become synonymous with IDEO's practices of Design Thinking and as such the term while in popular use is technically a reference now to Ideo's approach to collaborative design practice.
In their own words "IDEO did not invent design thinking, but we have become known for practicing it and applying it to solving problems small and large." ref: https://designthinking.ideo.com
You'll be more successful in your search in looking at the larger academic fields that encompass Design Thinking. Specifically 'CoDesign', 'Participatory Design, 'Service Design' and 'Design Research'.
The Design Research Society (DRS) founded in 1966 is a learned society committed to promoting and developing design research. They are a good source of design research of the types you are asking about.
You can access their digital library of design research papers here (https://dl.designresearchsociety.org/) and you should be able to find some papers of interest.
Muhammad Taufiq Amir Muhammad, Yes, look at Richie Khoo's resources. Also I highly recommend study of IDEO's experience applying what they learned. - Others speak of ideas that sound the same but lack insight from the experience of applying the idea. And the insight to know how it applies and is modified to different needs. Also, searching ResearchGate itself you'll find many versions of your same question and the corresponding commentary.